HSL Harpur Hill Buxton SK17 9JN

HSL
Harpur Hill
Buxton
SK17 9JN
A workplace survey on the control of task
specific exposures to carcinogens, mutagens
and reprotoxins in the UK chemical industry
Report Number
HSL/2005/35
Project Leader: Chris Keen BSc LFOH
Author(s): Chris Keen
Science Group: Environmental Sciences
© Crown Copyright, 2005
PRIVACY MARKING:
Available to the public
HSL report approval:
Date of issue:
Job number:
Registry file:
Electronic filename:
Helen Chambers
September 2005
JS2002998
FSSU/RE/44/2002
K:\ckeen\wordpro\projects\short_term_exposures\final report
ACKNOWLEDGEMENTS
This project would not have been possible without the assistance of the UK chemical industry.
The author would like to thank the individuals and organisations visited for this project for their
time and co-operation.
iii
CONTENTS
1
2
3
4
5
6
7
8
Introduction ........................................................................................................................... 1
Methodology ......................................................................................................................... 3
2.1
Substance selection ....................................................................................................... 3
2.2
Criteria for site selection ............................................................................................... 3
2.3
Topics covered during the visits.................................................................................... 4
2.4
The site visit .................................................................................................................. 4
Findings................................................................................................................................. 6
3.1
Review of studies carried out ........................................................................................ 6
3.2
Tasks studied ................................................................................................................. 8
3.3
Management procedures ............................................................................................... 9
3.4
Road tanker loading and offlloading ........................................................................... 12
3.5
Ship loading and offloading ........................................................................................ 15
3.6
Process and QC sampling............................................................................................ 16
3.7
Transferring to and from semi-bulk ............................................................................ 18
3.8
Maintenance tasks ....................................................................................................... 20
3.9
Laboratory activity ...................................................................................................... 21
3.10 Personal Protective Equipment ................................................................................... 22
3.11 Exposure monitoring ................................................................................................... 25
Discussion ........................................................................................................................... 30
4.1
H&S management systems.......................................................................................... 30
4.2
Controls applied to specific tasks................................................................................ 30
4.3
Task specific exposure monitoring.............................................................................. 32
4.4
PPE.............................................................................................................................. 32
4.5
General ........................................................................................................................ 33
Conclusions ......................................................................................................................... 35
Recommendations ............................................................................................................... 37
Appendices.......................................................................................................................... 38
HSL site visit report ................................................................................................................ 43
References ........................................................................................................................... 65
iv
EXECUTIVE SUMMARY
OBJECTIVES
This project was intended to provide an overview of the control of task specific exposures to
carcinogens, mutagens and reprotoxins (CMRs) where these materials are handled in bulk
quantities in the UK chemical industry. The work had 4 specific objectives;
To assess attitudes and awareness toward controlling task specific exposures.
To review typical control strategies for specific tasks
To collect industry task specific exposure measurement data
To identify good practice for controlling task specific exposures, and feed this back to industry
MAIN FINDINGS
Overall, the better health and safety performers visited for this work demonstrated a good
degree of understanding of the potential significance of task specific exposures, and the need to
control them. Generally, but not always, they were able to translate this into adequate exposure
control.
Of the tasks commonly studied, exposure control during road tanker (and ship) loading and
offloading was generally of a reasonable standard, although task specific measurement data
supplied for this task did indicate that significant exposures are possible, even where a good
standard of engineering control is employed. Uncoupling after the transfer is complete is the
most crucial stage, and it is necessary to control emissions at his stage to achieve adequate
exposure control for this task. The quality of controls during drum filling and emptying was
highly variable. The taking of QC samples was the routine task where controls were most often
deficient. Exposure control during maintenance tasks generally appeared adequate. The use of
permit to work systems and task specific risk assessments makes a positive contribution to
exposure control during maintenance tasks.
Where exposure monitoring is conducted, this almost always focuses around measurement of
full shift exposures. The measurement of task specific exposures is not commonplace in the UK
chemical industry.
RECOMMENDATIONS
Where CMRs are handled in enclosed plant, exposure controls need to be assessed on a task
specific basis, for each task where containment is breached. Task specific exposure
measurement is a useful tool for such purposes, and ought to be performed more frequently
across the chemical industry. Where highly toxic chemicals (such as CMRs) are handled in
totally enclosed systems, it offers detailed information on the degree of exposure control being
achieved at individual tasks which cannot be obtained from full shift monitoring.
The taking of QC samples was the single task for which, in general, exposure control
deficiencies were most frequently encountered and where improvements could be made.
v
This project has greatly increased HSE’s knowledge of what constitutes good practice for
controlling exposures to CMRs for tasks involving breaches of containment. Given the
seriousness of the health effects associated with failures of control for these substances, there
may be value in producing formal good practice guidance as part of the ‘Chemical carcinogens
project’, part of HSE’s ‘Disease Reduction Program’, based on the findings of this work. These
findings are relevant to any company handling CMRs, and may be especially useful to smaller,
independent organisations who may not have access to specialist occupational hygiene
expertise.
This project has provided evidence that generally there are lower standards of exposure control
at less regulated sites. Although some potentially serious deficiencies were observed at top tier
COMAH sites, in general, overall standards of exposure control were higher at those sites than
at lower tier COMAH sites, which in turn were higher than at the few sub-COMAH sites
visited. There may be value in considering this when planning interventions as part of the
‘Chemicals carcinogens project’.
vi
1
INTRODUCTION
Within the UK chemical industry, and especially amongst the sites regulated by the Control of
Major Accident Hazards Regulations 1999 (COMAH), high toxicity chemicals are generally
handled under near total containment. Nevertheless, there are routine tasks, at some point within
the process, where containment is breached for some reason. Such tasks include, for example,
the loading of road tankers, or the taking of process samples. Additionally, maintenance activity
often necessitates breaches of containment. Wherever containment is breached, or there is
unplanned loss of containment, there is the potential for workers to be exposed to the substances
held within the system. Such exposures referred to herein as task specific exposures, may also
be referred to as ‘peak’ or ‘short term’ exposures.
Exposure data supplied to HSE by industry has traditionally related to full shift exposures. This
approach reflects the fact that much exposure monitoring is conducted to assess compliance
with Occupational Exposure Limits (OELs), and almost always the 8-hour time weighted
average (TWA) limit is seen as the most important. Even where short term exposure limits
(STELs) exist, and they do not for many compounds, they would appear to be given less
consideration. However, full-shift exposure measurement generates no information whatsoever
on task specific exposures. Short duration peaks of high exposure are usually ‘masked’ when
full-shift monitoring is performed. Hence, it is not possible to use this information to target the
individual tasks, or items of plant, where improvements in exposure control are required.
Where processes are running under near total containment, almost all total exposure will come
from these short term discrete tasks involving containment breaches, and it is necessary to
‘crop’ these peak exposures to achieve further reductions in full shift exposures.
Clearly, the duration of tasks with exposure potential is highly variable, ranging from less than
one minute during breaking of a road tanker coupling, to several hours for some maintenance
jobs. The frequency with which such tasks are performed is similarly variable, some, such as
the taking of QC samples, may be performed several times per shift whilst certain maintenance
tasks may be one-offs, or only be performed once every several years.
The toxicological significance of task specific exposures is unclear, however there is some
evidence to suggest that brief, relatively high periods of exposure may be significant. They are
particularly relevant where high short term exposures can lead to serious acute health effects, or
are implicated in the development of serious chronic effects such as cancer or asthma. The
summary criteria document for butadiene, produced in support of the occupational exposure
limit for this substance, states that ‘the excess of leukaemia (among workers) has been found to
be consistently associated with peak exposures to butadiene. (HSE 1998). Professor Tom Smith
from Harvard School of Public Health identified that peak exposures may be of special concern
because of the high dose rate at the target organ within the body. High dose rates may alter
metabolism of the substance, overload protective or repair mechanisms or amplify the response
in the tissue. Professor Smith argued for more research in this area to develop better ways of
measuring peak exposure along with further toxicological research to understand which agents
are likely to present particular risks from high short-term exposures. (2001 Conference on
Exposure Assessment in Epidemiology and Practice Held in Göteborg, Sweden, June 10-13
2001).
A recent HSE investigation (unpublished) used continuous direct reading personal sampling and
video visualisation to investigate task specific exposures. This work, on a few sites only, has
shown that even on sites where good quality exposure control hardware is employed, task
specific exposures can be high. For high volatility materials, peaks in the region of 1,000 ppm
were measured, when breaking road tanker couplings and taking process samples. These results
1
were for a known carcinogen assigned a maximum exposure limit (MEL) of 10 ppm. Similar
results were found when transferring powders through hatches from bags to bulk reaction
vessels, short term exposures were shown to be very high and variable. The study highlighted
examples of poor practice, such as the taking of process samples, of known carcinogens, by
running into open vessels. Given the limited scope of the initial study, only 5 sites were visited,
plus the fact that these situations occurred at ‘good’ sites, with workers under the scrutiny of
HSE inspectors (which generally results in extra care being taken), the findings raised questions
regarding how well the chemical industry as a whole took note of, and controlled, task specific
exposures.
As a result, it was decided to conduct a much wider survey of the chemical industry to review
current control practices applied to the routine handling of certain classes of materials. The
project focussed on carcinogens, mutagens and reprotoxins (CMRs) as the COSHH regulations
require exposures to such substances to be reduced as far as is reasonably practical. This
requirement applies to all tasks where there is exposure potential, even when the task is brief.
Time segregation is not an acceptable exposure control for these classes of material. The main
aims of the work were :
1) To determine current awareness , attitudes and practices for controlling highly toxic
substances in the chemical industry.
2) To determine typical control strategies applied to these tasks, and review their
effectiveness.
3) To determine the profile of exposure via inhalation or skin contact, to highly toxic
substances during specific tasks, collecting industry measurement data, where available. .
4) To provide information on the good practice used by industries handling such
substances based on the survey findings.
This work focussed around a field study. Information on assessment, evaluation and control of
task specific exposures was collected from 40 sites within the UK where CMRs were handled.
Exposure by inhalation and dermal routes was considered. No exposure measurement was
performed as part of the work.
A secondary objective of this work was to assess compliance with the occupational exposure
limit for benzene at oil refineries and specifically to assess at these sites, the effects of reducing
this limit in recent years.
2
2
2.1
METHODOLOGY
SUBSTANCE SELECTION
This work focussed on a selected group of substances that are of high chronic toxicity. In the
main these were carcinogens, mutagens and reprotoxins (CMRs). This includes any substance
assigned one of the following risk phrases under the Chemicals (Hazard Information and
Packaging for Supply) Regulations ;
Carcinogens: R45 - May cause cancer,
R49 - May cause cancer by inhalation;
Mutagens :
R46 - May cause heritable genetic damage,
Reprotoxins: R60 - May impair fertility,
R61 - May cause harm to the unborn child,
R62 - Possible risk of impaired fertility
R63 - Possible risk of harm to the unborn child;
The work was targeted at CMRs which were felt to be significant from an occupational
viewpoint. The substances selected were therefore those which are manufactured or used in
large quantities and/or to which there may be potentially large numbers of workers exposed.
It was also decided to conduct a limited number of visits to sites handling lower toxicity
materials, with risk phrases;
R40 - Possible risk of irreversible effects
R48 - Danger of serious damage to health by prolonged exposure
R37 – Irritating to the respiratory system
These were included to see if there were any clear differences in the exposure control strategy
applied to these materials.
2.2
CRITERIA FOR SITE SELECTION
To determine common practices for assessing and controlling task specific exposures to CMRs,
it was considered necessary to visit a representative number of premises where these substances
are handled. This enabled assessment of the exposure control strategies employed by a range of
sites. Participation in the study was voluntary. One of the aims of this work was to identify good
practice for controlling task specific exposures to CMRs. In order to achieve this, the site
selection was deliberately biased toward sites which were perceived to be among the better
health and safety performers. It was also considered that such sites would be more likely to have
conducted task specific exposure measurement, and be prepared to share the results of these
measurements.
Forty sites were visited for this work, between February 2003 and December 2004. All sites
visited were regulated by HSE’s Hazardous Installations Directorate (HID). Four of the sites
were oil refineries. Although the control of task specific exposures was discussed at these
refineries, there was a dual reason for these visits in that HSE required information relating to
the effect of reducing the benzene MEL (reduced from 3 ppm to 1 ppm in June 2003). The
information relevant to controlling task specific exposures at these refineries has been included
3
in this report. A separate report is being prepared detailing the specific findings relating to the
changes in the benzene MEL (HSL report OH/2005/05).
All site visits were carried out by an occupational hygienist from HSL and many involved joint
visits with HSE Occupational Hygiene Specialist Inspectors or Operational Inspectors from
HID.
2.3
TOPICS COVERED DURING THE VISITS
Discussions during the visits were guided by a questionnaire, in order to ensure that all relevant
topics were covered during the visit. The questionnaire was key to the project. An initial version
was produced prior to the first visit (appendix 1). This was reviewed by the project team after 5
visits, and refined into a more user friendly version (appendix 2), which was used for the
remainder of the project. The questionnaire was sent to the site contact, often the health and
safety professionals at the site, prior to the actual visit, to allow preparation.
The questionnaire covered the main areas relevant to controlling task specific exposures. It
allowed the main tasks with exposure potential, and the exposure controls applied to these tasks,
to be identified. Health and safety management systems were covered, although only basic
information was collected on these due to the time restriction (each site was visited only once,
generally the visit lasted around half a day). Other areas discussed included the use of exposure
monitoring, and especially any task specific monitoring performed, and the selection, use and
maintenance of personal protective equipment (PPE).
During this project, exposure by inhalation and by skin contact was considered, as task specific
exposures are not limited to inhalation exposure only. Dependant upon the specific situation,
dermal exposure can be more significant than inhalation exposure. Skin exposure can occur in
several ways. These include direct chemical contact with unprotected skin, failure of PPE, or
inadvertent contact with contaminated items or re-use of contaminated PPE. As well as local
skin damage (dermatitis, chemical burns etc.) dermal exposure can be a significant route of
entry into the body, allowing the substance to cause subsequent systemic effects.
2.4
THE SITE VISIT
Each site visit involved an office based discussion, based around the questionnaire described
above. Generally, this took 2 to 3 hours. Relevant professionals from the site provided input.
Commonly these included, health and safety specialists, engineering specialists, operational
management, plant operatives and trade union representatives.
Following the office based discussion, the relevant plant areas were visited to review operations,
control procedures and equipment. At most sites, informal discussions were held with plant
operators to assess their awareness of the risks, working procedures and equipment used to
control those risks. Where practical, copies of written operating procedures and any other
relevant documentation (e.g. air monitoring results) were obtained. However, one of the main
focal points of each visit was to gather specific information on control hardware, and on the
site’s experiences of using that hardware. Site visits generally lasted around 3 to 4 hours, with 2
to 3 hours spent in the office based discussion followed by the inspection of the relevant areas
of the plant.
4
2.4.1
Reporting arrangements
For each visit, a number of reports were prepared. Each fulfilled a specific need. The formats
used are shown in appendices 3 to 6. These consisted of:
1) A ‘full report’ detailing the key information collected, the outcome of discussions and
site reviews, conclusions and recommendations. The template used to produce this
report is shown in appendix 3. This report was intended to capture comprehensive
information generated during the visit for use in the project, and for wider use within
HSE.
2) A ‘summary report’ indicating the key findings from the visits and any items that
required further consideration. The template used to produce this report is shown in
appendix 4. Copies of these were sent to the relevant HID Inspector to feedback to the
site.
3) A ‘matrix’ report that summarised the relevant information on control equipment in a
semi quantitative way from each visit. Two matrices were developed, one to deal with
exposure control hardware (see appendix 5) and to deal with ‘software’ issues (appendix 6).
A key to using these matrices can be found in appendix 7.
5
3
FINDINGS
NB – a database of selected, relevant information gathered during this project was compiled to
allow various statistical determinations to be made. Whilst it is recognised that there are severe
limitations in performing statistical analyses on a relatively small data set, and especially where
the data set has been skewed (in this case by deliberately selecting better H&S performers),
these determinations do provide some evidence of trends, and have been used in the following
sections when discussing findings. A copy of the coded database, together with a key to allow
interpretation, can be found at appendix 9.
3.1
REVIEW OF STUDIES CARRIED OUT
3.1.1
Breakdown by substance
Twenty seven different substances were studied during the site visits. These are listed in Tables
1 to 3, below. Although forty sites were visited, at some sites more than a single substance was
discussed, and hence a total of 65 ‘case studies’ were made.
Table 1 : Carcinogens studied
Substance
Acrylamide
Acrylonitrile
Arsenic
compounds
Benzene
Benzyl chloride
1,3 butadiene
Dimethyl sulphate
Ethylene
dibromide
Ethylene
dichloride
Ethylene oxide
Hexavalent
chromium
compounds
Hydrazine
Propylene oxide
o-Toluidene
Trichloroethylene
Vinyl chloride
8 hour
TWA OEL
0.3 mg/m3
(Sk)
2 ppm
(Sk)
0.1 mg/m3
1 ppm
(Sk)
0.5 ppm
10 ppm
0.05 ppm
(Sk)
0.5 ppm
(Sk)
5 ppm
(Sk)
5 ppm
0.05
mg/m3
0.02 ppm
(Sk)
5 ppm
0.2 ppm
(Sk)
100 ppm
(Sk)
3 ppm
STEL
‘R’
Phrase
*
No. of
studies
Carcinogen
classification
(IARC)
Physical
state at
STP
Boiling
point (when
pure )
None
R 45
5
2A
Solid**
N/A
None
R45
4
2B
Liquid
77°C
None
R45
1
1
Solid
N/A
None
R 45
8
1
Liquid
80°C
1.5
ppm
None
None
R 45
4
2A
Liquid
179°C
R45
R 45
2
6
2A
2A
Gas
Liquid
N/A
188°C
None
R 45
1
2A
Liquid
132°C
None
R45
1
2B
Liquid
84°C
None
None
R 45
R49
3
4
1
1
Gas
Solid
N/A
N/A
0.1
ppm
None
None
R45
1
2B
Liquid
113°C
R45
R 45
2
1
2B
2B
Liquid
Liquid
34°C
200°C
150
ppm
None
R45
1
2A
Liquid
87°C
R 45
4
1
Gas
N/A
6
Table 2 : reprotoxins studied
Substance
8 hour TWA
OEL
STEL
‘R’
Phrase*
Dimethylformamide
2-methoxy ethanol
(2-(2methoxyethoxy)ethan
ol
Nitrobenzene
n-Hexane
10 ppm (Sk)
5 ppm (Sk)
None
20 ppm
None
None
R61
R60
R63
1 ppm (Sk)
20 ppm
2 ppm
None
R62
R62
No. of
studies
Physical state
at STP
Boiling point
(when pure )
2
1
1
Liquid
Liquid
Liquid
153°C
124°C
Not known
2
1
Liquid
Liquid
210°C
69°C
Physical state
at STP
Boiling point
(when pure )
Plus 1 study on a pesticide active ingredient with R63 classification.
Table 3 : other substances studied
Substance
Aniline
Cyclohexanol
Dichloromethane
Formaldehyde
Hydroquinone
8 hour TWA
OEL
1 ppm (Sk)
50 ppm
100 ppm
(Sk)
2 ppm
2 mg/m3
STEL
‘R’
Phrase*
No. of
studies
None
None
300 ppm
R48
R 37
R 40
2
1
2
Liquid
Liquid
Liquid
184°C
161°C
40°C
2 ppm
None
R 40
R40
3
1
Gas**
Solid
N/A
N/A
*The R phrase listed in these tables is the one relevant to this project. Each of these substances
will carry a number of other R phrases.
**These materials are generally manufactured and handled in aqueous solution.
Four of the benzene studies were conducted at oil refineries.
The status of the OELs listed in Tables 1 to 3 changed when the revised OEL framework was
introduced in 2005. However, the limits listed in the table were in place and were being used by
industry as exposure control tools at the time of the visits. The limits for dimethylformamide, nhexane, nitrobenzene, cyclohexanol and hydroquinone were occupational exposure standards
(OESs), all of the other substances which were assigned limits carried MELs at the time this
work was conducted. Under the revised OEL framework, these have all been transferred to
workplace exposure limits (WELs). The limit for hydroquinione has been reduced from 2
mg/m3 to 0.5 mg/m3, a chemical hazard alert notice (CHAN) was issued temporarily whilst this
substance was reviewed. All of the other limits have been transferred unchanged into the revised
OEL framework and appear in the 2005 edition of EH40. For the majority of substances studied
in this project, virtually nothing has changed as the requirement to reduce exposure to ALARP
applies to all carcinogens and mutagens in the same way as it applied to all substances assigned
MELs under the old system.
Most of the substances studied were liquids at STP. However, these cover a wide range of
volatilities, from propylene oxide (bp 34°C) to o-toluidine (bp approx 200 °C) and nitrobenzene
(bp 210°C). Clearly, as volatility increases, the potential for inhalation exposure where
containment is breached also increases. Conversely, lower volatility substances would persist
longer on contaminated surfaces, thus increasing the potential for dermal exposure. In addition
to chronic toxicity, some of these substances may also have acute health effects (eg cyanosis).
Some can be detected by odour at extremely low concentration, others have no appreciable
odour until concentrations are several orders of magnitude above the OEL. Many of these
7
substances are flammable, which provides an additional incentive to users to maintain
containment.
3.1.2
Breakdown by site activity
The sites visited could be classified by activity (relative to the substances studied for this
project) as follows. For the purposes of this classification, carcinogens and reprotoxins have
been separated. Carcinogens, in this case, refer to either category 1 or 2 carcinogens (generally
speaking risk phrases R45 or R49). Thirty four of the sites visited handled this class of
materials, these may be broadly divided as follows ;
•
•
•
Manufacturers/producers of carcinogens from non carcinogenic raw materials – 9 sites.
Sites where the carcinogen is present in the raw material and in the final product – 11
sites (this includes sites where the carcinogen passes through the site physically
unchanged, i.e storage and distribution companies)
Users of carcinogens where the carcinogen is reacted out and is not present in the final
product – 14 sites.
As fewer sites were visited where reprotoxins, category 3 carcinogens and lower toxicity
substances were handled these have not been separated by activity, but may be broadly
categorised along the following lines;
•
•
•
3.2
Users/distributors/producers of reprotoxins – 6 sites (3 of these also handled
carcinogens)
Users/distributors/producers of category 3 carcinogens – 3 sites (1 of these also handled
reprotoxins)
Users/distributors/producers of lower toxicity materials – 1 site.
TASKS STUDIED
The tasks which carry the potential for exposure, and which were focussed upon during the site
visits, are listed below, together with the number of sites at which that particular activity was
studied.
Road tanker loading – 14 sites
Road tanker offloading – 20 sites
Ship loading – 3 sites
Ship offloading – 2 sites
Transfer from semi bulk containers into plant – 10 sites
Decant from plant into semi bulk containers – 9 sites
Sampling of raw materials – 11 sites
In-process and/or final product sampling – 34 sites
Making and breaking flexi hose connections for materials transfer – 1 site
Line breaks for maintenance – all sites
Vessel entries for maintenance/inspection – 21sites
Spills and cleaning up of spills – all sites
Decontamination of PPE/contaminated equipment – all sites
Clearly, depending upon the nature of their business, not all sites performed all of these tasks.
8
3.3
MANAGEMENT PROCEDURES
Health and safety management procedures relevant to controlling task specific exposures were
discussed during the site visits. These procedures were not investigated in depth, as the main
focus of this project was on the specific exposure controls employed to control task specific
exposures. The main findings regarding management systems are summarised in table 4. The
‘standard of practice’ has been rated into one of four categories. Good practice indicates well
developed systems, with only minor deficiencies. Adequate indicates that some, relatively
minor elements of the particular system may be poor, or missing. Poor indicates that only
extremely basic systems were in place, and ‘none’ indicates that no system exists whatsoever to
cover that particular aspect of H & S management.
Table 4 – rating of various elements of health and safety management systems
Standard of practice
Management procedure
None
Poor
Adequate
Good
Toxic hazard assessment
0
2
13
25
Written operating procedures
1
7
15
17
Incident reporting
1
1
9
29
H&S auditing
1
1
18
20
Operator training
1
3
8
28
Health surveillance
4
1
13
22
Many of the sites which have been classified in poor, or none categories in table 4 had multiple
failings relating to H&S managements systems, i.e the total number of sites which had at least
one element of their H&S management system classified as poor or missing completely cannot
be calculated simply by summing all of the ‘poor’ and ‘none’ ratings in table 4. In actual fact,
eleven of the sites visited had at least one element of their H&S management system rated as
poor, or non-existent. This included three top tier COMAH operators, although each of these
had only a single element of the H&S management system rated as poor or non-existent (one
had poor written operating procedures, the other two had serious deficiencies regarding health
surveillance procedures). Of the 6 lower tier COMAH sites visited, five received at least one
rating of ‘poor’ or worse, i.e only one of these was judged to have H&S management system
that was adequate in all aspects relevant to exposure control. Serious deficiencies were found at
all three sub-COMAH sites visited, two of these had multiple failings.
3.3.1
Toxic hazard assessment
The first stage in achieving adequate exposure control is recognition of toxic hazards. This was
generally, well developed for those sites running only a small number of established processes
involving substances with well documented toxicology. In these cases material safety data
sheets and other suppliers information are a common source of information to guide control
requirements.
Other sites, such as toll manufacturers, pharmaceutical companies and, to a lesser extent,
storage and distribution companies, may handle hundreds of materials, including unusual
intermediates and final products, which may have limited toxicological information. In these
situations, expert judgement is necessary for effective toxic hazard assessment. Some excellent
systems were encountered amongst such sites, most notably those within the pharmaceuticals
sector. Information was drawn from a number of sources. Some companies used structure
analogy relationships and a few carried out or commissioned toxicological testing. Of the sites
visited, some of the pharmaceutical manufacturers had the most comprehensive systems in this
area, with systems relying on ‘hazard banding’ according to toxicity. Each ‘band’ is assigned
9
an in-house exposure limit and the control hardware and operating procedures required to meet
that limit is specified, as are PPE requirements. Many factors were taken into consideration
within these systems but an important determinant was physical state with different control
approaches applied to solids, liquids and gases. A number of other, non pharmaceutical sites had
similar systems in place but generally these were less well defined and didn’t employ the formal
hazard banding system.
For some substances studied it was clear that user groups had been formed, either nationally or
internationally to provide generic guidance on safe operating procedures, plant and systems
involving those substances. Such groups met frequently to exchange information on
performance and to review operations related to the toxic substances being handled.
Systems for toxic hazard assessment were judged to be good at 25 of the 40 sites visited, and
‘adequate’ at a further 13 sites. Only 2 sites were deemed to have ‘poor’ systems in this area.
3.3.2
Written operating procedures
Where possible, examples of written operating procedures were obtained for tasks with the
potential for exposure to toxic substances. These varied greatly from extremely simple to
comprehensive step by step instructions, detailing exposure controls to be employed at the
relevant points of the task, including PPE requirements.
Generally speaking, where written operating procedures existed, operators were familiar with
them. In many cases they were effective tools in ensuring that tasks were carried out in a
standardised way that ensured risks were controlled. They were also useful training tools, both
for new operators and as refreshers for more experienced workers.
One general failing was the lack of a specific written procedure for dealing with spillages of
CMRs. Only eighteen of those visited indicated they had specific written emergency procedures
for dealing with the specific substance under discussion. Fifteen sites had generic spillage
procedures, which were designed to be applied to all spills, irrespective of the substance and had
not reviewed these to see if they were suitable for especially hazardous CMR substances. Seven
sites appeared to have no formal procedure for dealing with spills. Material safety data sheets
were cited as potential sources of information in the event of a spillage. However, these would
not usually provide sufficient detail on exposure control, and little (if any) information on
decontamination of an area after gross clean up. Only a small minority of sites had given
consideration as to how to check the adequacy of decontamination after a spillage clean up
The quality of written operating procedures was judged to be ‘good,’ at 17 sites, and ‘adequate’
at a further 15. However, written operating procedures were judged to be of a ‘poor’ standard at
7 sites, i.e they were extremely basic and did not address the need to control operator exposure,
and 1 site had no written procedures of any description (this was one of the smallest sites
visited, and one of only three non COMAH sites).
3.3.3
Incident reporting
Most sites had some form of incident reporting and investigation procedures in place. These
ranged from informal systems based on oral communication, which would have to be classified
as poor practice, to formal, structured systems.
Where formal systems did exist, these were almost always electronically based. The better
systems graded incidents with respect to the severity, identified individuals to investigate and
10
included systems to ensure that corrective actions were implemented. These generally,
demanded a formal ‘close-out’ procedure. Often, the large, multi site companies, shared
information from incident investigations between sites and in responsible care cells in a bid to
prevent recurrences in their industry. At a number of sites, near miss reporting was actively
encouraged.
High personal exposure results were dealt with as incidents by some companies. These incidents
were graded, ranging from minor to severe, dependant upon the exposure result. For example,
several companies would treat results in the range 50 to 100% of the OEL as a near miss.
Results in excess of the OEL would be treated as actual incidents. In these cases, the high result
would be fully investigated, the reasons for the result identified and any corrective action taken
to reduce the possibility of the situation being repeated.
Incident reporting/investigation systems were judged to be of a good standard at 29 sites, and
adequate at a further 9 sites. At one site, systems were judged to be poor, and one site had no
incident reporting system whatsoever (again, this was one of the small, non COMAH sites).
3.3.4
H & S auditing
The majority of sites reported internal audit systems that included health and safety
arrangements as an integral part of the audit programme. The frequency, content and
compositions of the teams involved was very variable. The larger companies carried out both
routine site audits with site teams consisting of relevant specialists and were also subject to
higher level parent company audits of equipment, systems and procedures. Others reported less
sophisticated audit procedures involving internal resources only and little, if any, specialist
input.
Similarly actions on audit results were variable. Several reported formalised procedures with
senior site management responsible for owning the reports and actions from them and for
signing off compliance. Some were more ad hoc but still required formal closure and acceptance
of defined actions.
Twenty sites were judged to have systems for auditing health and safety topics which were
‘good’, with a further 18 having adequate systems. At one site, the systems were judged to be
poor, and one site had no formal auditing systems whatsoever (again, this was one of the
smaller non COMAH sites).
3.3.5
Operator training
Operator training standards varied greatly on the sites visited. At the poor end of the spectrum,
some sites provided only informal, undocumented ‘on-the-job’ training (i.e. the bare basics
required to operate the plant). Conversely, some examples of excellent training systems were
also found, and at such sites it was clear from discussions with plant operators that this resulted
in a good knowledge of the plant and the health and safety considerations attached to operating
it. Refresher training, generally speaking, tended to be more ad-hoc than initial operator
training. However, a number of the sites visited did have well structured systems in place for
refresher training.
Some sites included very little on toxic substances in their training, whilst others paid great
attention to this subject, producing tailor made packages on the COSHH regulations and on
conducting COSHH assessments. RPE training was fairly common, and at all the sites visited,
anyone using BA had received training. Less common was training on use and maintenance of
other PPE (chemical resistant gloves and oversuits). Most sites documented training, i.e.
11
maintaining training files etc. Less common was validation of training to ensure that the
messages had been received and understood.
The quality of operator training was judged to be ‘good’ at 28 sites, and ‘adequate’ at a further 8
sites. At three sites, the quality of training was judged to be poor, and one site had no systems
for training whatsoever (again, this was one of the small, non COMAH sites).
3.3.6
Health surveillance
The value of health surveillance with regard to carcinogens is somewhat restricted, and this is
acknowledged by HSE. Nevertheless, some form of health surveillance is appropriate for
workers handling carcinogens. (HSE 1999, HSE 2002)
Most of the sites visited did conduct some form of health surveillance. Pre-employment
medicals based on questionnaires were used by most, but not all companies. Routine medicals
were carried out by about half the sites visited but these often consisted of a general health
check, possibly including lung function testing and skin inspection. Health surveillance schemes
were not often specifically tailored to the risks posed by any particular substances handled on
site. Some sites conducted substance specific health surveillance, but this was usually where
there was a legal requirement to do so, such as for vinyl chloride, or specific HSE guidance. A
number of sites had amended their health surveillance programs to take into account the quality
of their exposure controls, i.e where extensive personal exposure monitoring had consistently
indicated a high degree of control, the level of health surveillance had been reduced. A small
minority of sites apparently conducted no health surveillance whatsoever, not even a preemployment medical.
The quality of health surveillance programs was judged to be good at 22 sites, and adequate at a
further 13 sites. One site was deemed to have a poor quality health surveillance program, and
four sites conducted no health surveillance whatsoever.
3.4
ROAD TANKER LOADING AND OFFLLOADING
Road tanker offloading was studied at 20 sites. The materials being offloaded were all liquids,
but these do include some solids in aqueous solution and some liquefied gases under pressure.
The majority of these sites (16) were handling substances that were carcinogens (R45, R49), but
deliveries included reprotoxins (R62) and irritants (R37). Road tanker loading was studied at 14
of the sites visited. Ten of these were loading carcinogens (R45 or R49) substances, the other 4
were loading either category 3 carcinogens, reprotoxins or irritants. Six of these sites were
‘splash loading’, via open hatches in the tanker top.
Tanker loading/offloading facilities seen during this work were variable but generally
incorporated outdoor, segregated facilities. Spillage containment provisions were present at all
locations, usually incorporating bunded areas and dedicated drainage to the site effluent sumps.
Most sites reported some form of drive-away protection procedures. These ranged from simple
vehicle key retention and physical barriers to sophisticated interlock systems that closed down
loading activities if vehicle movement was sensed.
The loading and offloading of road tankers is a task with clear exposure potential, and was
generally studied at all sites where it was performed. Clearly, close attendance of operatives to
the unloading/loading activities is necessary for significant periods.
12
Exposure potential is particularly high during uncoupling, following the transfer. Any residual
material left inside loading hoses and couplings is opened to atmosphere, at a time when the
operator is in close proximity. The use of dry break coupling systems, or the methods described
above for clearing lines after transfer, should minimise the potential for exposure at this stage.
Discussions with operators at a number of sites during this project indicated that uncoupling can
be achieved with no visible release of material. However, other evidence was collected that
shows that on occasions, significant exposure peaks are occurring. Examples include ;
At one site offloading highly volatile carcinogens, visible plumes were observed during
uncoupling.
Another site, handling ethylene oxide (a gas at STP, with an 8 hour TWA MEL of 5 ppm),
reported typical exposure peaks around 20 ppm during uncoupling, with exceptional peaks
of several hundred ppm when offloading lines were not adequately purged before breaking
the coupling.
Information from another site, loading acrylonitrile (a volatile liquid with an 8 hour TWA MEL
of 2 ppm) onto road tankers, indicated exposures as high as almost 10 ppm, averaged over
the 90 minute loading duration. This would result in an 8 hour TWA exposure in excess of
90% of the MEL as a result of this single loading operation.
HSE have measured peaks of almost 1,000 ppm during uncoupling of butadiene tankers, a gas at
STP with an 8 hour TWA MEL of 10 ppm. Dry break couplings were in use on this
occasion.
All of these results relate to inhalation exposures. The potential for exposure by this route
increases as the volatility of the substances handled increases. However, should residual
material remain in the loading hose and coupling when uncoupling, there is also potential for
significant dermal exposure.
The storage vessels, into which tankers are offloaded, were fitted with overfill alarms at nearly
all sites visited, with many installations also incorporating automatic overfill cut-out
systems. A few of the sites (4) also had vapour recovery or scrubber systems connected to
the vent units of the storage tanks.
The usage of various key elements of exposure controls is summarised in table 5.
Table 5 : Usage of key elements of exposure control for road tanker loading/offloading
Procedural controls
Leak test Blowing/rinsing
of
clear of lines
couplings prior to breaking
3
8
9
16
Loading
Offloading
No.
of
sites
14
20
3.4.1
Procedural controls
Engineering controls
Vapour
Dry break
return
couplings
systems
8
9
13
4
PPE
Use of RPE
during
uncoupling
4
9
Gloves
during
uncoupling
14
20
As can be seen from table 5, road tankers were being loaded at 14 sites. Only 3 of these leak
tested the transfer hose and coupling prior to loading. Eight of these cleared the loading hose
and coupling by either blowing through with gas or rinsing with water, prior to breaking the
connection after loading, the remaining six simply allowed the loading hose to drain under
gravity before breaking the coupling.
13
Road tankers were being offloaded at 20 sites. Nine of these leak tested the transfer hoses and
coupling prior to each use. Sixteen of these cleared the hose and coupling by either inert gas
blowing or water rinsing prior to uncoupling, the remaining 4 allowed the hose to drain under
gravity.
3.4.2
Engineering controls
Dry break couplings were used at less than half of the sites visited. A variety of reasons were
given for this limited use. These included:
a) Cost (they are more expensive than other coupling systems)
b) Compatibility through the supply chain (if road tankers are fitted with dry break couplings
then the site loading the tanker and the site receiving the tanker must both be able to deal
with them)
c) Manual handling issues (they are considerably heavier than other types of coupling)
d) Perceived unreliability (at one site offloading gaseous products dry break couplings had
been observed to leak).
When using bolted flanged tanker connections, flexi hoses were almost universally used to link
the road tanker to the fixed plant. These afford the flexibility to maintain a gas tight coupling as
the road tanker height alters as it is loaded or unloaded.
Eight (out of 14) sites employed some form of vapour return/recovery system for tanker
loading. In 2 cases, this was an LEV system used in conjunction with open loading, at the others
a sealed coupling was made between the vapour return line and the tanker. Of the 6 sites loading
tankers with no vapour return, three were loading aqueous solutions of solids (no potential for
vapour formation), one was loading cyclohexanol, (not a CMR), one was loading o-toluidine
and one unleaded petrol (containing a maximum of 1% benzene). Nine sites used dry break
couplings couplings for tanker loading.
Thirteen (out of 20) sites were using vapour return systems to minimise emissions during
offloading activities. Of the ones who were not, 1 was offloading a mixture containing around
2% benzene, 1 offloading aqueous acrylamide, 2 formaldehyde, 1 benzene in coal tar (0.5% but
at 70°C), 1 nitrobenzene, 1 glycol ethers. No site was offloading neat, liquid carcinogens
without vapour return. Four sites used dry break couplings, the remainder used bolted, flanged
connections.
These results indicate that vapour return systems are commonplace when transferring volatile
materials to and from road tankers. Most commonly, these consisted of a hose linking the road
barrel to the storage tank, allowing the head space vapour from the vessel being filled to be
displaced into the headspace of the vessel being emptied. Less frequently, these vented to
atmosphere through some kind of scrubber or vapour recovery system.
3.4.3
PPE
The most crucial task in terms of exposure potential is the uncoupling of tankers after loading
(see below). For this, RPE was worn at 4 (out of 14) sites loading tankers, and 9 (out of 20)
offloading them. Gloves were worn universally during uncoupling. At some sites, operators
attending loading/offloading operations wore chemical protective oversuits and gloves
throughout the operation, with RPE close to hand.
14
3.5
SHIP LOADING AND OFFLOADING
Six of the sites visited were either loading or offloading carcinogens from ships. However, at
three of these sites the shipping operations were contracted out and were not under direct
control of the site, and so could not be discussed in detail during the visit.
Of the three sites where shipping activities were studied in detail, 2 were performing both
loading and offloading, one was loading only. Substances involved for this task included VCM
(offloading and loading, at 2 different sites), benzene (loading) propylene oxide (offloading) and
aniline (loading). Hence, a total of five scenarios were studied. Aniline does not carry
carcinogen classification.
In terms of exposure control, there are many parallels between ship loading and road tanker
loading. However, one significant difference is the quantities involved. Whilst a road tanker
typically holds 25-30 tonnes of material, ship-shore transfers typically involve several thousand
tonnes. The transfer of such quantities is clearly a highly hazardous activity, for a variety of
reasons.
Only very limited task specific exposure data was collected for this activity but this tended to
support the data supplied for road tankers, indicating that significant inhalation exposures can
occur during uncoupling, even where attempts have been made to clear the lines and couplings.
Data was obtained for two of the five scenarios investigated. The site loading benzene (volatile
liquid, 8 hour TWA MEL 1ppm) onto ships had measured peaks as high as 12 ppm using spot
reading stain tubes held in the operators breathing zone during disconnection. The site
offloading VCM (a gas at STP), 8 hour TWA MEL 3 ppm) had measured peaks as high as 1500
ppm using a photo ionisation detector, again this was during disconnection. This data is
discussed more fully in appendix 8 (see sites 30 and 34).
Additional task specific monitoring data was obtained from two of the refineries visited (sites
39 and 40), although the ship loading operation was not studied at these sites. Site 39 had
measured task specific benzene exposures in the range 35 to 40 ppm (averaged over sampling
period of 15 minutes) during ship disconnection, and butadiene exposures in the hundreds of
ppm (and in extremes in excess of 1,000 ppm), averaged over approx. 30 minutes sampling
time, during ship disconnection. These data are for personal samples, using pumped sorbent
tube sampling. RPE was in use for these tasks, and will have gone some way to actually
reducing the true exposure experienced by the operator. Site 40 had measured lower benzene
exposures, typically around 4 ppm averaged over a 15 minute period, during ship disconnection,
although this site had only a limited number of data points (n=2) for this activity.
During these visits, anecdotal evidence was supplied which suggested that exposure control
standards on board the ships may not be as high as the standards observed on the shore. Manual
dip sampling from, and level gauging of, ships storage tanks would appear to reasonably
common. This could not be investigated in detail at any site, since in all cases the ships were not
owned by the sites being visited, and the ships crew were employed by another company.
3.5.1
Procedural controls
Where it was studied, all sites had well developed procedures for ship loading and offloading.
The high risk nature of the task resulted in comprehensive written operating procedures being
developed at all three sites. The transfer lines and ship-shore connections were leak tested in all
but one of the cases studied, the exception being the loading of aniline where the site felt the
risk associated with pressurising the lines outweighed the risk due to a leaking connection. In all
15
five cases, the loading hoses and couplings were blown clear prior to breaking the coupling
once the loading/offloading operation was complete.
3.5.2
Engineering controls
In all four situations investigated where carcinogens were involved, vapour return lines were in
use. They were not used for loading aniline, the ships tanks vented to atmosphere during this
transfer. Dry break couplings were not used at any site, bolted, flanged, gasketed connections
were used by all.
3.5.3
PPE
As with road tankers, the task of uncoupling the ship once the transfer is complete is one area
where there is potential for significant exposures to occur. RPE and chemical protective gloves
were worn at each site during disconnection of the coupling after the transfer.
3.6
PROCESS AND QC SAMPLING
Almost all of the sites visited, at some stage, took samples of material which either definitely, or
potentially, contained a CMR. This is a task with clear exposure potential. A wide range of
sampling devices were encountered, these are summarised in table 6.
Table 6 : engineering controls applied to QC sampling
No sampling
Raw
material
sampling
In process
sampling
Sealed or semi
sealed system
21
0
Open
system
with engineering
controls
1
3
3
4
Open system, no
engineering
controls
7
21
Mixture
0
9
It would appear that measurement of task specific exposures during sample taking is extremely
uncommon, very little useful data was obtained for this activity. Some task specific exposure
data for QC sampling was supplied by site 39 (see appendix 8). These indicated benzene
exposures around 2 ppm (over a 20 minute sampling period), when sampling unleaded petrol,
although the sampling technique used is unclear.
The vast majority of sampling systems studied were for liquid sampling. The sampling of R45
category solids was encountered at only 2 sites, both were handling granulated materials which
were not particularly dusty. In both cases manual scooping was the sampling method employed.
The operative were wearing gloves and transferred the solid from the scoop to bags or screw
topped jars/cans for transport to the laboratory.
This study confirmed that the taking of process samples is one task which is routinely
performed at most sites handling chemicals. Overall, the results show that open sampling
systems are still reasonably common, even when the process involves CMRs. These findings
strongly suggest that it is an area where task specific exposures are not being controlled as well
as they should be. Once again, it is an activity where task specific monitoring would be useful
in determining the adequacy of control.
16
3.6.1
Procedural controls
An effective control method to reduce exposures during sampling is to remove or reduce the
need to sample at all. For raw materials, this can effectively be achieved by accepting the
material on the basis of a ‘Certificate of Analysis’, couple with the use of trusted suppliers and
hauliers. Of the 29 sites using CMRs as raw materials, 21 chose this option. However, for the
others, raw material sampling systems were generally poor, with dip sampling (of road tankers
or IBCs/barrels) being the ‘norm’. Six of the 7 substances being sampled in this manner carried
R45 classification (2 were solids, 4 liquids).
Whilst it would be impractical for most sites to adopt a ‘no sampling’ policy for their own
products, the number of samples taken can be minimised by making a structured study of the
sampling regime and questioning the need for each sample taken. This had been done on a
number of the sites visited, allowing them to reduce considerably the number of sampled taken
on the site, and so reduce the potential for exposure associated with sample taking.
3.6.2
Engineering controls
Only one site had managed to install a satisfactory in-line analysis system. Three sites used
proprietary sealed or semi-sealed systems for all CMRs across the site. Four sites used
engineering controls for sampling CMRs across the site. Twenty one of the sites took some, or
all, process/QC samples using open sampling systems, with only PPE as exposure control. The
remainder of the sites had a mixture of sampling systems for CMRs. Several sites
manufacturing lower toxicity products, where CMRs were amongst the raw materials, worked
on the assumption that as QC samples are only taken at advanced stages of the reaction, the
potential for exposure to reactive raw materials is removed since they will no longer be present
in the material being sampled. Under normal operating conditions this is probably valid.
However, should the reaction not proceed as planned then there is a chance that the sample will
contain substantial amounts of unreacted CMR. Hence, it is prudent to wear PPE as a precaution
where this approach is adopted. At a number of sites where this method was used, the
concentration of unreacted CMR in the sampled material was unknown. Sites made
assumptions, ranging from ‘a few ppm’ to ‘perhaps a few percent in some samples’. At the top
end of this range there is still substantial CMR exposure potential attached to handling the
sampled material, and open sampling must be critically appraised. If this method is adopted,
testing to quantify unreacted raw materials should be done, not necessarily on each sample, but
as a confirmation of the potential risks and hence the controls that might be required.
Most of the sampling systems encountered during this project employed some form of
recirculating loop, to remove the need to run off material in order to obtain a representative
sample. Clearly, it is desirable for sampling points to incorporate this feature, any excess
material run off prior to sampling is a potential source of exposure.
Less common than recirculating loops was some form of cooling system, to reduce the
temperatures of the sampled material (where the sample was being taken from reactors
containing material at elevated temperature). Again, this is a desirable feature, from a safety
point of view in addition to reducing exposures.
Some well designed sampling systems were seen. Generally, for mobile liquids, these are
proprietary systems which either use a needle to inject the sample through a septum into a
sealed bottle, or the sample bottle is screwed onto the sampling point during filling. With the
screw on bottle type there is brief potential for exposure when the bottle is removed and capped.
Some sites who had tried the needle and septum system reported that the needles can become
blocked, and this can lead to significant exposure and inconvenience from cleaning regimes. To
17
a large extent this depends upon the product and the presence of suspended solids or viscous
condensation products.
Sealed ‘sample bombs’ were commonly used for gaseous materials. Provided these are regularly
tested to verify the integrity of seals and valves, these provide a means of gas sampling with
very little exposure potential.
Some of the extracted, enclosed sampling systems observed would provide good exposure
control. When designing and installing such a system the site should always be aware that, as
with any LEV system, capture will be much more efficient if the exposure source is
contained/enclosed so far as possible.
3.6.3
PPE
Gloves were worn at all sites for sample taking, irrespective of the methodology employed. Less
common was the use of RPE, 11 sites reported using RPE for sampling.
3.7
TRANSFERRING TO AND FROM SEMI-BULK
Chemicals are delivered to sites in semi bulk containers (IBCs, drums, sacks) in situations
where they are not used in large enough quantities to be delivered by road tanker, or
occasionally where there is no bulk on-site storage tank to allow road tanker delivery. Finished
products are packaged into such containers to suit customer requirements. The emptying and/or
filling of semi-bulk containers is a task with the potential for exposure.
There is a large variety of equipment available for this operation. Facilities can range from
closed transfer systems often with additional local exhaust extraction arrangements to minimise
emissions, through to open, manual drum emptying/filling. Table 7 summarises the use of
engineering controls for this activity.
Table 7 : engineering controls applied to semi-bulk transfers
Drum emptying
Drum filling
Number of
sites
10
9
Automated,
enclosed system
2
1
Good quality
LEV
3
3
Poor quality
LEV
4
4
None
1
1
A limited amount of task specific measurement data was obtained for drum filling and
emptying. Two sites with a good standard of engineering control (laminar flow booths)
provided results which showed inhalation exposures during drum emptying to be relatively low.
However, data from another site, with a much lower standard of engineering control, indicated
potentially very high exposures (see sites 1, 20 and 28 in appendix 8).
The findings for these tasks indicate that exposure potential during semi-bulk handling
operations is generally higher than during bulk transfer. The operation generally requires more
operator input, and the degree of containment is typically less. Furthermore this activity is likely
to be performed at smaller sites, with less knowledge and resource dedicated to exposure
control.
3.7.1
Procedural controls
The applicability of procedural controls to this task is limited, although performing the task
outdoors, and physical segregation, would fall into this category. Unfortunately, information on
18
the use of these controls was not collected in sufficient detail to be able to supply an accurate
analysis of the use of their use.
3.7.2
Engineering controls
Ten of the sites studied in this project had CMRs delivered in semi bulk containers on a fairly
regular basis. The substances concerned were, in all cases, either solids or low volatility liquids.
Four sites handled solids in this way. Methods of transferring solids from semi-bulk into plant
varied. Three of these four sites were relatively small operations, among the smallest visited for
this project. The substances involved at all three sites were hexavalent chromium compounds.
At all three sites, the raw material was manually tipped from drums/sacks into the plant. Two of
the three had LEV systems but these were poorly designed, providing very little enclosure of the
exposure source. The third site had no engineering control whatsoever. This reflects the
relatively ‘low-tech’ approaches employed at such sites. The solids being handled were either
granules or crystals, not finely divided powders, this will have some effect on controlling
exposures.
The fourth site handling solids in this manner was a substantially larger operation They had
installed an automated drum handling system which opened, emptied and washed out drums
under near total containment. This had been custom designed and installed at high capital cost.
This system virtually removed all exposure potential during drum emptying and by water
washing the drums afterwards (the solid in use at this site was water soluble) it also reduced the
potential for exposure as a result of handling contaminated ‘empty’ drums.
At the six sites which were transferring liquids from semi bulk containers into the plant, a
variety of methods were encountered for this activity. Hoses fitted with rigid lances were fairly
common. However such systems were employed in a variety of environments, from usage on
open plant to being used within segregated laminar flow booths. A number of systems were
seen with ‘on-tool’ extraction fitted to the lance, these did appear to provide reasonable capture
of vapour at source. One system was seen whereby a fixed ‘Cam-Lock’ type connection was
made to an IBC, with the fitting piercing a previously sealed membrane as the connection is
made, thus providing a means of connection with virtually no exposure potential.
Nine sites were filling semi bulk containers with CMRs. Again, the substances were mainly
either solids or low volatility liquids, although one site was visited where aqueous formaldehyde
solutions (38% w/w), and neat dichloromethane (bp 40°C) were being filled into drums. The
two sites filling solids into drums/sacks were both handling hexavalent chromium compounds.
One had highly automated systems, with a high degree of enclosure and extraction. At the other
site the material was manually dropped into drums with an LEV system (only partially effective
due to poor enclosure of the exposure source) in use.
The filling of liquids into IBCs/drums generally had some form of LEV applied to the task.
Some very effective systems were encountered, either using ‘on-tool’ extraction on the filling
lance or some form of custom designed filling station, fitted with LEV and a good degree of
containment of the exposure source (the open neck of the container being filled). Such systems
would appear to be fairly common at sites where semi-bulk containers are regularly filled. At
the other end of the spectrum, situations were observed where drums were being filled with only
a flexible arm type extraction system in use, resulting in poor control at source.
19
3.7.3
PPE
PPE use for transferring to and from semi bulk containers was variable. Gloves were worn at all
sites for this activity. RPE use was not so common, 6 sites used it for emptying drums/IBCs, 5
sites used RPE during filling of drums/IBCs.
3.8
MAINTENANCE TASKS
Breaches of containment for maintenance activities are common at chemical sites. Dependant
upon their exact nature, such work can have the potential for much higher exposures than
routine activities associated with production. Containment breaches may be of longer durations,
and unexpected situations are more likely to occur. Recent HSE research indicated that loss of
containment and uncontrolled releases is often related to maintenance activities (Collins and
Keeley, 2003). This work indicated around 17% of all cases studied were related to
maintenance activities. Maintenance activity may be performed by site employees, or it may be
carried out by contractors. Occasionally, maintenance may involve items being sent off site for
repair or service.
3.8.1
Procedural controls
The vast majority of the sites visited had well developed management and procedural systems
associated with maintenance tasks. Permit to work (PTW) systems were the norm. These
frequently required the production of a task specific risk assessment, hence exposure control
(plus all other relevant H&S risks) should be considered on each occasion that a PTW was
produced.
In general, most sites made attempts to clear lines, vessels, and other items of plant, before
breaching containment for maintenance. A substantial proportion went further, subsequently
water rinsing the line and or blowing through with air or nitrogen. Some sites repeated this cycle
several times. In general, the area around the containment breach would be isolated by closing
and locking valves. One site took samples of the plant washings, only authorising the first break
when these indicated satisfactory decontamination.
At a minority of sites, it was standard practice to issue direct reading toxic gas/vapour
measuring instruments to operators breaching containment for maintenance. These were
generally fitted with audible alarms, to allow early indication should the work lead to the
emission of toxic gas/vapour. Provided such equipment is regularly calibrated, and is reliable, it
is clearly good practice to employ it in these circumstances.
3.8.2
Engineering controls
Generally, engineering controls play only a minor part in controlling exposures during
maintenance. Occasionally, mobile extraction systems may be employed, but this is unusual.
3.8.3
PPE
Some sites assumed that after clearing lines and equipment, no residual material would be
present and then proceeded to make the line break with few, if any, further exposure controls.
Conversely, at other sites, the highest level of PPE available was still worn when making the
first break, typically this would include chemical resistant oversuit, wellingtons and gloves, with
all seams taped, in conjunction with air fed BA. Some sites continued to wear the full PPE
ensemble throughout the maintenance task. Others conducted some kind of atmospheric testing
20
after the first break (using direct reading instruments or stain tubes) or visual inspection prior to
reducing the level of PPE for the actual maintenance task.
3.8.4
General comments
Where the task involves a vessel entry it would generally be given a much greater deal of
consideration than a line break on open plant. Clearly, there is much greater potential for an
acutely life threatening situation to occur, and the Confined Space Regulations (HSE 1997)
apply. The AcoP accompanying these regulations indicates that measurement of toxic gases or
vapours should be performed if the atmosphere may be contaminated or to any extent unsafe to
breathe. Without exception, all of the sites visited measured oxygen levels in vessels prior to
entry. Some sites also measured the gas/vapour concentration of the substance previously held
in the vessel. A variety of techniques were employed for this measurement, including stain
tubes, instruments lowered into vessels in buckets, and sampling onto pumped sorbent tubes
with laboratory analysis. RPE requirements for the vessel entry were then made based on the
results of these measurements. However, of the 21 sites where vessel entry procedures were
studied, 6 measured only oxygen, they made no measurement of toxic gas/vapour that had been
contained within the vessel. In the worst cases, 2 of these sites subsequently entered vessels
without RPE based on measurement of oxygen content only. This is clearly poor practice.
Many of the sites visited had procedures to decontaminate equipment that was sent to third
parties off site for refurbishment /repair/servicing. Where decontamination was not practical
without such equipment being dismantled, several sites had a tagging and alert system to warn
recipients of the potential risks of contaminants that might be released during servicing
activities. One company had produced a DVD that was sent to relevant service contractors to
warn them of the dangers of substances they might encounter and to explain the tagging system
to the contractor. The information also included the contact number for relevant advice on the
safe working requirements.
3.9
LABORATORY ACTIVITY
Although of relevance to this project, laboratory activity was not studied in the same depth as
the individual tasks discussed in the preceding sections. On a number of sites it was not possible
to study lab activity, either due to time constraints or due to problems gaining access to the
laboratory areas. For these reasons, the information collected relating to lab activity can be
regarded as a summary overview only.
Almost all sites visited had on-site laboratory facilities to allow rapid analysis of QC samples.
These ranged from rather basic facilities housing a handful of simple instruments to moderate
sized laboratories equipped with a variety of modern analytical equipment.
Significantly, for the sites with good quality exposure monitoring programs, lab staff were
frequently identified as a worker group with 8 hour TWA exposures toward the top end of the
range for the site. This is probably a result of the length of time that they are potentially
exposed. It would typically take an analyst more time to analyse a QC sample within a lab than
it would take a plant operator to obtain the sample, especially if some form of sample work-up
procedure is performed. On a number of sites, the lab analyst was also responsible for the taking
of QC samples. This raises their exposure potential even higher.
21
3.9.1
Procedural controls
Only limited information was collected relating to procedural exposure controls in labs. The
storage of ‘waste’ material from QC samples was common in laboratories, this material was
often tipped into a drum of some description. On most sites this vessel was stored inside a fume
cupboard, but situations were observed where this material was stored in the open laboratory or
on some occasions in segregated storage units/rooms in the laboratory area. Occasionally the
controls in these areas were not adequate to contain spillages, or to control vapour releases.
Once a certain amount of waste has been accrued it is either disposed of (as chemical waste) or
returned to the process through some sort of inlet on the plant. Situations were encountered
where this task carried some exposure potential and controls were often less rigorous than at
other points on the plants.
3.9.2
Engineering controls
Most of the labs which were seen had some form of fume cupboard, extracted work bench or
local exhaust extraction units. These units varied greatly in design and at the majority of sites,
but not all, were routinely maintained and tested in order to control performance.
Generally QC samples containing CMRs were handled inside fume cupboards, although
situations were observed where such samples were handled on the open bench, despite fume
cupboards being available.
3.9.3
PPE
Typically polyester cotton laboratory coats were worn by laboratory workers. PPE is
downgraded in laboratories, and where chemical protective gauntlets are used to take QC
samples out on the plant, surgical type gloves were generally used for sample handling within
the laboratory. The reasons for this are understandable, as laboratory tasks frequently require a
high degree of manual dexterity and precision. However the significantly lower chemical
protection afforded by such PPE should be borne in mind in relevant risk assessments.
There was no usage of RPE in laboratories at any of the sites visited.
3.10
PERSONAL PROTECTIVE EQUIPMENT
PPE in this instance relates to chemical protective equipment. This includes RPE, chemical
protective gloves and chemical protective clothing.
In accordance with the hierarchy of control philosophy, PPE should generally be the ‘last line of
defence’ in terms of exposure control. However, where containment is breached and
carcinogens are involved, PPE will play a part in the overall exposure control strategy.
Some of the sites visited used PPE as the primary exposure control for certain tasks. Most
commonly this applied to the taking of QC samples. Maintenance on decontaminated plant was
conducted at a minority of sites, with total reliance on PPE, and this is a practice which should
be critically reviewed when potential exposures to carcinogenic chemicals are involved.
Reliance on PPE should always be the last option and especially so for CMRs. There are
situations where the use of PPE is appropriate, and occasionally essential. On a number of sites
visited, PPE was used as a secondary exposure control, in addition to engineering controls, as a
precaution in case of an unforeseen event, for example to protect operators in the event of an
unplanned release during offloading of road tankers.
22
Generally speaking, most of the sites visited had structured selection processes for PPE. PPE
manufacturers and/or suppliers advice had generally been sought regarding compatibility with
the chemicals handled. Material safety data sheets (MSDSs) were commonly used to guide PPE
selection, although the quality of data supplied in these documents is variable. There is a duty
on chemical suppliers to identify suitable PPE for users of their products, and to provide this
information on MSDSs. Suitable glove materials should be specified (EU Commission
Directive 2001/58/EC), although a high proportion of MSDS do not contain this level of
information, and it is common for them to include the statement ‘wear suitable gloves’, thus
requiring the user to perform their own selection.
For operational/maintenance and contractor staff, risk assessments were used to guide the
selection procedures for PPE. Often the selection and usage procedures were the responsibility
of on-site committees consisting of specialists, operational management and workforce
representatives. At some sites, PPE ‘user groups’ had been set up, to allow an exchange of
information and opinions between site management, safety officers and end users. PPE is more
likely to be accepted where workers clearly understand the reason for using it and where they
have been consulted on the equipment provided. Involving users in the selection process
provides feedback on the true performance of PPE in use. For example, although a pair of
gloves may offer good chemical protection, they will be of limited use if they are so thick that
they do not allow the required level of manual dexterity to operate equipment (HSE, 2001), or
on the other hand, are so thin that they frequently tear.
3.10.1
Gloves
In terms of dermal protection, gloves are perhaps the most important item as it is the hands
which are most likely to receive contamination. This can occur from deliberate immersion, or
from inadvertent splashing or handling of contaminated items. At none of the sites visited were
gloved hands immersed into any of the CMRs studied. However, several instances were
encountered where known contaminated items were deliberately handled with gloved hands.
It was fairly common amongst the sites visited for chemical protective gloves to be disposed of
on a daily basis, and several of the sites had a splash and dispose policy, whereby contaminated
gloves are immediately removed and disposed of. However, several sites re-used gloves on
more than one day, for periods of up to several months in extremes. It would be very unusual
for any glove manufacturer or supplier to provide permeation data for periods of longer than 8
hours, as this is typically the maximum period for which glove materials are permeation tested.
Hence, where gloves are used for longer than this, there is uncertainty regarding the degree of
protection they will offer. There is also the possibility of exposure as a result of permeation of
material which has previously contaminated the gloves, also from handling contaminated gloves
when donning. PVC gloves were very common, despite the fact that on occasions, other
materials had been identified as providing better protection. This is probably driven largely by
cost and convenience.
Examples of poor glove selection were encountered, notably the use of cotton cuffed gloves for
chemical protection. If the cuffs of these become contaminated, they very effectively ‘wick’ the
contamination inside the glove, where it remains in intimate contact with the operators skin in a
moist, humid environment which provides good conditions for dermal penetration.
At several sites, most notably storage and distribution companies, operators may work with
several different substances in a single working shift. It may not always be practical for them to
constantly change gloves from one type to another. Under such circumstances, glove selection
may need to be somewhat of a compromise, taking into consideration the substances handled
and the potential for glove contact.
23
3.10.2
Chemical protective oversuits
A variety of chemical protective oversuits were encountered to protect against the various
substances encountered during these visits. These ranged from disposable single use items,
through to full body, air supplied suits. Many premises reported appraisal procedures and
written guidance to guide selection and use of oversuits. All provided segregated storage and
welfare facilities to help with care of clothing and general welfare. A number of sites had ‘inhouse’ PPE laundries, where used oversuits are laundered and inspected between uses. These
were generally well run facilities, where the potential for exposure with incoming contaminated
items was adequately considered and controlled by a combination of procedural and engineering
controls.
Commonly, during the site visits the company contacts were unaware of the material from
which their oversuits were made and the specific protection offered. Many of them referred to
them as providing protection against a range of chemicals at their sites. Clearly suits are often
designed for protection against a single class of substance and commonly will not be suitable
against a variable range of substances.
Discussions on maintenance of oversuits indicated differing approaches. Some sites routinely
wash them down after each use in dedicated wash areas. Some would only wash down if the
suits were known to be contaminated. Some sites had on-site laundering facilities whilst others
sent their suits off-site. Generally, contamination was removed by water washing before the
suits were bagged /dispatched for more rigorous cleaning. It was common practice for heavily
contaminated oversuits to be disposed of, rather than laundered, although in practice this degree
of contamination should be unusual.
Re-usable oversuits were more commonly encountered than disposables usually because they
were believed to offer better protection. However several companies preferred chemical
resistant disposables. The reasons given for this related to cost, wearer comfort and knowledge
that operatives used a clean suit each time.
3.10.3
Respiratory Protective equipment (RPE)
In general, RPE selection procedures were reasonably sound. Air fed equipment was common
for use against CMRs. Some sites had total ‘bans’ on the use of filtered RPE to prevent it’s
misuse, and simplify the selection process. Other sites had a complex range of RPE available for
different purposes. This kind of system requires a high degree of training and awareness of
everyone involved in the use of RPE, to guard against incorrect selection and use of the
equipment. Generally, where BA was in use, it appeared to be well maintained and the users
were well trained.
Where filtering respirators were selected, the quality of the maintenance regime was more
variable. At the better end of the spectrum, respirators were cleaned and inspected after each use
by a specialist facility. However, at other sites, the respirator maintenance regime was less
formal and not in compliance with COSHH regulation 9.2. There was much variation in the
frequency with which the filter cartridges are changed. This ranged from changing after a single
use (for all cartridge types), to sites where cartridges were used intermittently for periods of
several months. This is poor practice, especially for gas/vapour cartridges as contaminant begins
to diffuse through the filter bed from the first time of use. At a small minority of sites, examples
of incorrect cartridge choice were encountered, most frequently the selection of general organic
vapour cartridges against low boiling point substances for which AX cartridges are required. A
24
number of sites had conducted RPE fit testing, a number of others were in the process of
organising this. However, some sites were unaware of the legal requirement to perform fit
testing for those respirators where face fit was necessary to ensure effective protection.
3.11
EXPOSURE MONITORING
Personal monitoring of exposures is an effective method of demonstrating the adequacy of
exposure control. Where a measurement method is practical, i.e. inhalation or biological
measures, and exposure might be significant then some form of personal monitoring should be
used. Although static monitoring systems, hand held spot reading devices, and regular checks
on operating parameters of engineering controls can all play a part, none of these take into
account some of the human factors which can have a significant influence on an individual’s
exposure. For carcinogens the importance of exposure monitoring is explicitly stated in
paragraph 22 of Appendix 1 of the COSHH 2002 AcoP, which deals with control of
carcinogenic substances. This states clearly that ‘monitoring employees exposure to
carcinogens is normally necessary because of the increased risk of serious health effects if
controls fail’.
An anonymised summary of all exposure monitoring data obtained during this project can be
found in appendix 8.
Traditionally, exposure monitoring has focussed mainly on measurement of full shift potential
inhalation exposures, using personal air sampling, within the operators breathing zone. The
majority of exposure measurements taken by HSE, and the majority of data supplied to HSE by
industry, is of this form. However, where chemicals are handled in enclosed systems, all
exposures will be related to the individual tasks where containment is breached. Although full
shift monitoring can be used to monitor compliance with 8 hour TWA exposure limits, it reveals
little about the magnitude of these task specific exposures. Measurement of task specific
exposures is an extremely useful tool in such circumstances.
The monitoring of personal exposures was reviewed as a key part of each visit and the findings
are summarised below.
3.11.1
Full shift inhalation exposure monitoring
As indicated above, the majority of exposure monitoring programs focus on measuring full shift
inhalation exposure, using personal air sampling. In terms of demonstrating compliance with
occupational exposure limits, this is the generally accepted technique.
21 sites were judged to have adequate exposure monitoring programs, mainly focussing on
measurement of full shift exposures. Several, clear examples of good practice in the area of
exposure monitoring were observed, including :
i) The use of exposure monitoring to validate that exposure controls are effective wherever a
new process has been set up, or a working practice or item of plant has been modified.
ii) Ongoing programs of personal monitoring, with all worker groups frequently monitored.
iii) Monitoring results stored and exposure trends analysed.
iv) Results always communicated back to individuals.
25
v) In-house ‘action levels’ set (often below regulatory limits) and any result exceeding these
investigated in the same way as an accident/near miss.
vi) Use of calibrated, data logging, pocket sized direct reading instruments for all tasks with
exposure potential. These were fitted with audible alarms to indicate immediately when high
exposures are encountered.
However at some of the sites the picture was less satisfactory and findings are indicated below:
i) Eight sites had conducted no exposure monitoring whatsoever.
ii) At five sites, the last exposure monitoring exercise was conducted several years ago, or
inadequate monitoring had been performed.
iii) At 3 sites, direct reading instruments were relied upon totally for exposure monitoring which
had not been calibrated since they were purchased.
iv) At 2 sites, spot reading, colorimetric tubes were the only form of ‘exposure monitoring’
conducted.
A common deficiency, even at the sites where adequate monitoring was being performed and
the results recorded, was the lack of supporting ‘contextual’ information stored alongside the
results. Ideally, this would include a description of the tasks being performed by the workers
monitored, the duration of these tasks, any exposure controls in use and any other information
relevant to the individual’s exposure. This type of information is essential for meaningful
interpretation of monitoring results. A number of occasions were encountered during this
project where monitoring results were available without this type of information. In situations
where the individual conducting or overseeing the monitoring exercise have moved on, this
dramatically reduces the value of any monitoring results in demonstrating adequacy of
compliance.
3.11.2
Task specific exposure monitoring
The usage of task specific exposure monitoring at the sites visited was not particularly common.
Around 10 sites had task specific exposure results which were of adequate quality. As discussed
above, the measurement of task specific exposures can provide key data on the effectiveness of
control actions. However, measuring these exposures can also be challenging, dependant upon a
number of factors. Anyone embarking upon a program of task specific monitoring must give
careful prior consideration to the choice of measurement method. Significant factors include the
substance to be measured, the likely exposure levels, the duration of the tasks of interest and the
presence of any potential interferants. In extreme cases, for low volatility substances and
extremely short duration tasks, for example the taking of a single QC sample lasting perhaps
two minutes, it is questionable whether any measurement technique is capable of providing
valid results.
At the sites visited where task specific monitoring had been performed, a variety of
methodology had been employed. The techniques most frequently applied to task specific
monitoring are discussed in sections 3.11.2.1 to 3.11.2.3, below.
3.11.2.1
Spot reading, colorimetric tubes.
A number of sites used these devices, for various purposes. They are useful for indicating
approximate peak exposures and identifying exposure sources or emission points. However they
26
have several limitations and must be used with caution. They require the user to make an
informed judgement regarding which parts of the task carry greatest exposure potential. As hand
held devices, the sampling position must also be considered, and will only be meaningful with
respect to personal exposure, when samples are taken in approximately the workers breathing
zone. They have no use whatsoever in quantifying exposures over any timed period. They are a
useful tool for the purposes described above, but cannot be used to accurately quantify task
specific exposures.
3.11.2.2
Direct reading instruments.
Again, these were in use at a number of sites. A variety of operating principles are available.
The most common types utilise either a photo ionisation detector (PID) or an electrochemical
cell. PIDs respond to a wide range of organic gases and vapours. This feature allows them a
wide range of applicability but, at the same time means that they are prone to interference, thus
limiting their usefulness when a number of substances are present. They cannot, for example, be
used to accurately measure benzene in situations where petrochemical mixtures are handled. On
a number of occasions during this project, it was apparent that users of such instruments
believed that because their instrument had been calibrated for a single substance, then it would
not be affected by the presence of other substances. This is not the case. Even when calibrated
for a specific substance, PIDs will respond to a range of other organics if they are present.
Electrochemical cells are more specific than PIDs, but may still be prone to some degree of
interference. They are only available for a limited range of substances.
Direct reading instruments may be hand held, or, if small and lightweight, may be carried in the
operator’s breathing zone. In the latter case, if the instrument is capable of logging
concentrations versus time, then it offers a powerful tool for measurement of task specific
exposures. Such devices allow the total exposure over the duration of the task to be quantified
and provide information on the magnitude and duration of any significant exposure peaks within
the measurement period.
No matter what it’s measurement principle, any direct reading instrument must be periodically
recalibrated according to manufacturers instructions if it is to remain a valid measurement tool.
It may also be worthwhile requesting from the manufacturers, any validation data they have for
their instrument. Several HSE studies have been performed which demonstrate that
commercially available instruments do not always offer the level of performance suggested by
the manufacturer or supplier.
3.11.2.3
Sorbent tube sampling
Traditional sorbent tube sampling techniques, with subsequent laboratory analysis, may be
applied to the measurement of task specific exposures. This approach is least likely to suffer
from interference from other substances, and is potentially the most accurate and sensitive
approach. To be of use in measuring task specific exposures, the sample must be taken over the
duration of the task of interest only. It is unlikely that diffusive (passive) sampling will be
applicable to task specific monitoring. Owing to the short duration of the tasks typically being
measured, pumped techniques are more likely to offer adequate performance.
Before beginning a program of task specific monitoring, the user must consider these factors
and select an appropriate measurement method. Incorrect method selection at his stage will limit
the usefulness of the measurement results. Incorrect measurement methodology may provide
results which be meaningless or even worse, provide a significant underestimate of true
exposures.
27
3.11.2.4
Use of task specific monitoring
Around half of the sites visited had attempted some form of task specific monitoring. However,
at a number of these, the methodology used was questionable (stain tubes, uncalibrated hand
held instruments). At other sites only a very limited amount of task specific monitoring had
been performed, thus rendering the data of limited use. As with full shift monitoring programs,
the measurements must be repeated on a number of occasions to generate results which are
representative. A single measurement result is meaningless.
Around a quarter of the sites visited in total, were able to provide task specific measurement
data which was of reasonable quality, although most of these could not claim to have an
accurate picture of all task specific exposures occurring on site (relevant to the substances being
discussed during the visit). Most of the sites with reasonable quality task specific monitoring
programs in place were sampling over the exact duration of the task in question, i.e if it was a
two minute job then a 2 minute sample was taken, if it was a 30 minute job, then sampling
would be performed over 30 minutes. One site appeared to have standardised on a 15 minute
sampling period for measuring all task specific exposures, to allow results to be directly
compared with an in house 15 minute exposure limit. However. This approach may be
restrictive at times and not allow the full potential of task specific monitoring to be realised.
Two sites in particular stood out as having particularly high quality task specific exposure
monitoring programs. The first one of these involved the use of direct reading, data logging
personal monitors. These were carried by all operators, at all times where there is potential for
exposure. These are regularly downloaded, and the exposure profiles studied and any exposure
peaks are investigated. This system had allowed the site to identify occasions when working
practices had not been correctly followed. It had also allowed them to identify critical times
during certain maintenance activities when unavoidable exposure peaks were occurring, thus
providing evidence for the continued need for a high level of RPE at these times.
The second example of good practice in this area involved a site where, at the time of our
project visit, and for several months preceding that, task specific monitoring was performed for
all tasks, with exposure potential. This site used pumped sorbent tubes with on-site laboratory
analysis, to monitor. Their aim is to build up a database of task specific exposures, and use these
data to determine the tasks where current RPE usage was not necessary, and other tasks where
working practices ought to be reviewed with a view to reducing exposures.
A small minority of the other sites visited had conducted programs of task specific monitoring
in the past to identify tasks with exposure potential. However, once this monitoring had
achieved its aim, they had quite legitimately discontinued it.
3.11.3
Biological monitoring
Biological monitoring (BM) was not frequently encountered on the sites visited. This technique
can be especially useful in assessing exposures by all routes. It can also be applied
retrospectively to estimate exposures associated with unplanned events, such as the cleaning of
spills etc. as samples can be obtained post task. For some substances biological techniques have
not yet been developed or validated. However, BM techniques do exist for a number of the
substances studied in this project, including; acrylamide, aniline, arsenic, benzene, chromium,
dichloromethane, dimethylformamide, 2-ethoxy ethanol, n-hexane, o-toluidine and
trichloroethylene.
28
3.11.4
Static gas detection systems
Static gas detection systems were reasonably common. However, the majority of these were
installed to detect potentially explosive concentrations, providing an indication in terms of
lower explosive limit (LEL), and typically alarming at around 10% LEL. Although there are
clearly, highly valid reasons for installation of this type of equipment, it is of little value in
detecting leaks which are significant in terms of operator exposure. The LEL of an organic
gas/vapour is typically of the order of 1-2%, i.e 10,000 to 20,000 ppm. Hence, a detection
system providing an alarm at 10% LEL will require a vapour concentration of 1,000 to 2,000
ppm before alarming. Given that the OELs of the majority of substances studied in this project
are below 10 ppm, the limitations of this type of equipment are clear. Only 4 of the sites visited
had static sensing systems which were designed to respond to low ppm levels of vapour, i.e the
types of airborne concentrations that are considered significant in terms of operator exposures.
Three of these were handling carcinogenic gases, 2 vinyl chloride, one ethylene oxide, with
systems set to alarm at between 15 and 50 ppm. The other site was handling dimethyl sulphate,
and had installed a static monitoring system set to alarm at 35 ppb. Whilst static detection
systems are of limited use in assessing operator exposures, they are a powerful tool in guarding
against over exposure, providing the detectors or inlet lines are sensibly located and the system
is well maintained and regularly calibrated.
29
4
4.1
DISCUSSION
H&S MANAGEMENT SYSTEMS
The majority of sites visited for this project, 31 from 40, were top tier COMAH operators.
These sites were generally selected to provide information on good practices in controlling
CMRs and to gauge attitudes and practices in controlling task specific exposures to CMR. Such
sites have frequent contact with HSE, and other regulatory bodies. Generally speaking, these
sites had good overall management procedures and strategies for controlling risks from
exposure to chemicals, studied in this work, ranging from reasonable to excellent. As discussed
in section 3.3, three of the top tier COMAH sites were found to have a serious deficiency at
some point within their H&S management system. Deficiencies in H&S management systems
were much more commonplace at lower tier COMAH sites, and even more common at subCOMAH operators. Multiple deficiencies existed at two of the three sited visited in this latter
category.
Perhaps unsurprisingly, awareness and understanding of the COSHH Regulations, the
underlying ‘hierarchy of control’ principle, and other relevant H&S regulations and the
provision of equipment, procedures, and expertise ranged from inadequate to excellent. It was
not practical, however, in this work to analyse all the detail of relevant risk/COSHH
assessments and control actions required under Regulations. Hence specific activities involving
breaches of containment of chemicals were used as pointers to current awareness, attitudes and
practices for controls.
4.2
CONTROLS APPLIED TO SPECIFIC TASKS
4.2.1
Loading and offloading of road tankers and ships
Generally, exposure controls for these tasks were judged to be of a reasonably good standard
across the sites visited, although deficiencies were identified at certain sites. Open
loading/unloading of carcinogens without vapour return or LEV systems cannot be described as
reducing exposures to ALARP, the only exceptions being the transfer of solids in aqueous
solution and possibly very low volatility organic liquids. More task specific exposure
measurement data was obtained for this task than any other studied. This data showed that
significant exposures may occur, even where high standard of engineering control is applied.
Unsurprisingly, the disconnection between the road tanker (or ship) and the loading lines after
the transfer is complete is usually the single activity where exposure potential is highest. Careful
control of emissions at this stage by thoroughly clearing transfer hoses and couplings, most
usually by blowing with inert gas or less frequently by water rinsing, is essential in order to
achieve adequate exposure control.
4.2.2
Quality control sampling
The taking of process samples is a common activity. This study has revealed this to be an area
where task specific exposures are frequently not well controlled. Even at the ‘good’ sites visited
for this work, open sampling systems were often employed at some stage of the process. There
30
is potential for exposure by both dermal and inhalation routes with these systems. Gross
contamination of gloves was commonplace with open sampling systems.
The potential for inhalation exposure during sample taking would be dependant on the content
of the CMR in the sampled material and upon a number of factors, including:
•
•
•
the volatility of the material being sampled,
the temperature of the sampled material (frequently samples are hot, thus increasing
evaporation of volatile components) and
the length of time the sample vessel is open to atmosphere before being capped.
Clearly however, there is the potential for high peaks of exposure. In the worst cases, sampling
systems were observed whereby the hot sample was transported to the laboratory in an open
vessel, which was not lidded at any time. At other sites, sampling systems were seen whereby
the sampled material, which contained a significant proportion of CMR, was at a temperature
close to, or in excess of, the boiling point of the CMR, clearly resulting in rapid evaporation
from the sampling vessel. A number of sites visited had experimented with in-line analytical
instruments for QC analysis, allowing the product to be analysed without any need to breach
containment. Generally however, they had not been able to obtain acceptable performance from
such systems, indicating that, whilst theoretically this is a desirable method of QC validation, in
practice it is extremely difficult to operate reliably.
4.2.3
Transferring to/from semi bulk
The quality of exposure controls observed for this task varied greatly. The better sites
demonstrated that a good standard of exposure control is possible for this task. However, some
very poor situations were also observed. Custom built hardware is a necessary element in
controlling exposures for this task, as with all of the other tasks studied in this work.
Automated, enclosed drum filling facilities would generally provide the highest degree of
control in normal operation. Where these are not possible, and the operation requires more
manual input, then a good standard of LEV is required. Typically this would be some form of
‘on-tool’ LEV, fitted to the filling/emptying lance and providing good enclosure around the
open neck of the drum. Extracted booths may also provide adequate control, provided they are
used correctly. However, the use of portable, ‘flexible arm’ type LEV systems is inadequate
when CMRs are being transferred. It is widely recognised that his type of LEV is highly
dependant upon being correctly positioned for it to achieve efficient capture, and such systems
are frequently misused.
Any of the manual drum filling/emptying systems described here would possibly need to be
augmented by the use of appropriate PPE, including RPE. A task specific risk assessment,
including measurement of inhalation exposures associated with the task, would be required to
inform the PPE selection process.
Some of the larger operators seemed reluctant to pack product into semi bulk containers (drums
or IBCs), preferring to export bulk quantities by road tanker from the site. However, if there is
commercial demand for such materials to be supplied in smaller quantities, companies further
down the supply chain will be involved in decanting bulk quantities into smaller pack sizes.
These smaller organisations may generally receive less regulatory attention than larger sites, and
there is much anecdotal evidence to suggest a general lowering in standards at such sites.
31
4.2.4
Maintenance
The need to control exposures during maintenance activity was generally well recognised, with
the majority of sites following the hierarchy of control for such tasks. Most of the sites visited
were probably achieving adequate control during most maintenance tasks, using a combination
of working practices, engineering control and PPE. However, the general lack of task specific
measurement data for maintenance means that the majority of sites have no evidence to support
this. The fact that maintenance tasks are frequently subject to task specific risk assessment, as
part of PTW systems, may be significant in ensuring that exposure control is considered
adequately. Failure to measure airborne toxics prior to vessel entries is a clear example of poor
practice.
4.3
TASK SPECIFIC EXPOSURE MONITORING
Exposure monitoring in general was an area where deficiencies were not uncommon. Where
personal monitoring was done, the vast majority of data supplied during site visits related to full
shift monitoring to demonstrate compliance with 8 hour TWA OELs. Only around half the sites
visited had exposure monitoring programs which were deemed adequate.
Measurement of task specific exposures was not common. Only around 25% of the sites visited
had any meaningful task specific monitoring data, and this data was fairly sparse at most of
these. The number of sites using task specific monitoring as regular tool in their exposure
control armoury was disappointingly low.
The main reasons for the lack of task specific monitoring would appear to be :
i) Monitoring regimes are geared to demonstrate compliance with OELs and are based around 8
hour TWA limits. In this context it is worth noting that many of the sites visited for this project
made good use of OELs, and had a good understanding of the related principles.
ii) The techniques of sampling and analysis of full shift average exposures are well validated for
many of the substances studied. Conversely, dependant on the substance in question and the
tasks of interest, it may be technically difficult, even impossible, to perform task specific
monitoring. Even where the techniques are available the results cannot easily be interpreted
against recognised standards or exposure limits.
At the sites where good quality task specific measurements have been made, the results had
generally been used to decide the adequacy of controls and guide any necessary improvements.
The uptake of biological monitoring across the sites visited was surprisingly low. Given it’s
usefulness in allowing total systemic dose to be assessed, taking into account all exposure
routes, it would appear that biological monitoring would provide a useful tool for sites handling
CMR materials and is currently an under used tool.
4.4
PPE
Glove selection was possibly one area where improvements could be made. Although many
sites claimed to take glove manufacturer’s advice when selecting gloves, PVC gloves were very
common even though generally they are not best for chemical protection. Re-use of gloves for
several days was not unusual. This is questionable practice, given that permeation test data is
only ever available for a maximum of 8 hours.
32
Where it was employed, BA was generally well managed and used. Management and usage of
filtering RPE, although generally of an adequate standard, was less rigorous. Although not
common, incorrect RPE cartridge selection was encountered. Use of filter cartridges for
unacceptably long periods, especially against organic vapours, occurred at a significant number
of sites. Fit testing appeared to be becoming more common as the project progressed. This is
perhaps explained by the fact that fit testing only became a legal requirement in late 2002.
Several sites did not use filtered RPE, preferring to stick with BA and hence remove confusion
regarding selection.
4.5
GENERAL
Across the forty sites visited for this work there was a varying degree of attention to the control
of task specific exposures. The regulatory requirement, under the COSHH regulations, for the
control of carcinogens is to reduce exposure as low as reasonably practicable. Time segregation
is not an acceptable exposure control, and the ALARP principle should be observed for each
individual task with exposure potential. Although this condition was met for many activities
seen during this work, in a significant proportion of examples studied this was not the case.
Where local exhaust ventilation systems were in use for controlling exposures during
containment breaches, the majority of sites visited had these systems maintained and examined
in accordance with COSHH regulation 9.2. However, it must be borne in mind that the 14
monthly examination and test required by this regulation is intended to show that the system is
continuing to perform as originally intended. It provides very little information as to the
effectiveness of the LEV system in controlling exposures, which is significantly affected by
process parameters, human factors and the original design of the LEV system, none of which
are considered in the 14 monthly exam and test.
The fact that, even at the good performers visited for this work, problems were seen in
identifying and controlling task specific exposures suggests that, across the chemical industry as
a whole, significant levels of poor practice in controlling such exposures may be occurring. It is
important to note that the two companies seen in this study that were considered to be
controlling exposures to chemicals poorly, were two of only three sub-COMAH sites visited.
Although firm conclusions cannot be drawn from such a small sample, this finding is
nevertheless potentially significant, suggesting an area where HSE may perhaps focus attention
in the future.
The reasons for deficiencies in exposure controls were varied but in the main could be described
as either ignorance of the problem, lack of resources and poor maintenance or use of existing
controls. The first of these would be solved by employment of a competent occupational
hygienist, which is discussed further below. Lack of resources is more problematic, but may be
an indicator of relatively low priority afforded to exposure control within some organisations.
Poor maintenance or incorrect use of existing controls should be addressed by improvements in
the quality of H&S management (introduction of more rigorous maintenance programs) and
better operator training.
An important factor in recognising the need to consider task specific exposures appears to be the
employment of competent health and safety professionals, including Occupational Hygienists.
Most of the sites judged to have better than adequate exposure control strategies had in-house
occupational hygiene expertise. Some of companies achieved this through the use of a group
health and safety resource. Other sites had achieved a high standard of exposure control without
an in-house hygienist, generally through combining the skills of other health & safety and
33
engineering specialists already employed. However, a common factor at the sites with the most
serious exposure control deficiencies was the lack of professional in-house hygiene expertise.
34
5
CONCLUSIONS
(i)
It must be borne in mind that for the most part, site selection for this project was
biased toward sites which were perceived to be among the better health and
safety performers to allow good practice to be identified and in an attempt to
maximise the amount of quantitative task specific measurement data obtained.
Therefore the findings cannot be taken to be indicative of the performance of
the chemical industry as a whole, which is almost certainly somewhat lower
than might be suggested from the sites visited for this work
(ii)
The top tier COMAH sites (which formed over 75% of the sites visited for this
work) generally had reasonably well developed management systems with
respect to exposure control, although deficiencies were observed at some such
sites. In general, exposure control standards were somewhat reduced at lower
tier COMAH sites, and reduced further at the few sub COMAH operators
visited. Although it is not possible to draw firm conclusions based on this small
sample set, the poor practice observed at sub COMAH operators handling
CMRs supports the case for intervention in this sector to reduce the risk from
CMR exposure.
(iii)
In general, sites employing a full time occupational hygienist had less
deficiencies in their overall exposure control approach, and where deficiencies
did exist they were generally of a less serious nature, than sites where a general
health and safety manager took responsibility for these issues alongside all of
his/her other duties.
(iv)
The quality of health and safety training (and the delivery of that training)
provided to operators varied greatly across the sites visited. Clearly, this has the
potential to heavily influence operator behaviour on the shop floor.
Encouragingly, at a good proportion of the sites visited, operators appeared to
be knowledgeable and conscientious regarding the need to control exposures to
hazardous substances.
(v)
Most sites generally had well developed procedures for loading and offloading
of road tankers and ships. This usually resulted in reasonably good exposure
control for these tasks. Uncoupling the tanker after the transfer is complete is a
stage with particularly high potential for exposure, and emissions at this stage
must be carefully controlled. Exposure control standards during drum filling
and emptying were variable. The taking of QC samples was the area where
exposure control deficiencies were most frequently identified. It would appear
that this relatively low profile task may be overlooked on sites where other
significant hazards exist.
(vi)
Exposure control during maintenance tasks was generally of a reasonable to
good standard. Permit to work systems incorporating task specific risk
assessments had a positive contribution towards this. Most of the sites visited
made all reasonable attempts to clear lines and equipment prior to breaching
containment for maintenance. A significant deficiency linked to maintenance
was the failure to measure toxic gas/vapour levels prior to vessel entry. It must
be remembered that in this scenario, measurement of flammability is not
sufficient to protect human health. It is especially poor practice to enter vessels
35
with no respiratory protection based only on oxygen measurement, a situation
which was reported at a small number of the sites visited.
(vii)
Despite clear requirements under COSHH to monitor exposure, especially
where carcinogens are handled, inadequate exposure monitoring programs were
common on the sites visited. Problems ranged from a total absence of any
monitoring, to more subtle issues such as incorrect selection of sampling
methods, use of uncalibrated instrumentation or inadequate recording of
supporting contextual information. On a number of sites no monitoring had
been performed for several years and there was doubt as to whether the most
recent monitoring data reflected current exposures. The uptake of task specific
exposure monitoring was disappointingly poor. However, the sites where it had
been used had found it to be a useful tool.
(viii)
Generally, PPE was well selected, and tailored to the substances being handled.
PPE was generally well used and maintained. The most common failings in this
area were excessive re-use of ‘dipsosable’ items, specifically gloves and
respirator cartridges.
36
6
RECOMMENDATIONS
i) Where CMRs are handled in enclosed plant, exposure controls need to be assessed on a task
specific basis, for each task where containment is breached. Task specific exposure
measurement is a useful tool for such purposes, and ought to be performed more frequently
across the chemical industry. Where highly toxic chemicals (such as CMRs) are handled in
totally enclosed systems, it offers detailed information on the degree of exposure control being
achieved at individual tasks which cannot be obtained from full shift monitoring.
ii) The taking of QC samples was the single task for which, in general, exposure control
deficiencies were most frequently encountered and where improvements could be made.
iii) This project has greatly increased HSE’s knowledge of what constitutes good practice for
controlling exposures to CMRs for tasks involving breaches of containment. Given the
seriousness of the health effects associated with failures of control for these substances, there
may be value in producing formal good practice guidance should be produced as part of the
‘Chemical carcinogens project’, part of HSE’s ‘Disease Reduction Program’, based on the
findings of this work.
iv) These findings are relevant to any company handling CMRs, and may be especially useful to
smaller, independent organisations who may not have access to specialist occupational hygiene
expertise.
v) Although site selection was, in general, deliberately biased toward sites which were
perceived to be better health and safety performers some potentially serious deficiencies were
observed, even at top tier COMAH sites. Reduced standards of exposure control were observed
at lower tier COMAH sites and, generally the most serious deficiencies were observed at the
few sub-COMAH sites visited. This will need to be taken into account when planning
interventions as part of HSE’s ‘Chemicals carcinogens project’.
37
7
APPENDICES
Appendix 1 – initial version of questionnaire
1) INTRODUCTION
a) Objectives /strategy for project site visit and requirements from occupier.
(eg to collect subjective exposure profiles and control strategies for carcinogens and
related compounds. To review actual practices involving something like 50 sites The
current practices to be benchmarked after any required validation.
b) Outcomes/Outputs from work, short-medium-long
term.
(the data to be reviewed and collate; any non-conformances identified, to be signalled
up to relevant inspectors for review.
The meta data collated on an anonymous basis and made available to Industry.
Eventually the data will be used for the provision of good practice guidance on the
exposure profile and control strategies for carcinogens in the UK Chemicals Industry.
The target date for completion is mid 2004)
2) INFORMATION REQUIRED:
a) Company details:
Name
Address
(Comments
Small/Medium Large
HID Premise/Other
Comah Site)
b) Product details:
•
Representative Raw Materials/Intermediates/Products
(eg what substances on list are used or produced and under what conditions)
•
Hazard information
(eg MSDS)
•
Typical quantities involved in carcinogen transfer steps (grammes, kilo,
tonnes). Inventory of principal emissions/sources
(eg solids -dispensing, charging, unloading, milling blending, removal of
impurities, quality control sampling/testing
liquids- loading/ unloading tankers, rail cars, drum/semi-bulk containers,
small containers, pressurised liquid transfers, quality control sampling/
testing)
38
c) Operational/Process details:
•
Batch/continuous
(eg description of process and product type)
•
Equipment types used
(eg equipment chosen for containment by automatic transfer in closed systems,
manual interventions under safe working procedures? Process monitoring
automatic? Raw materials delivered in tanks, drums, bags etc?
•
Control equipment
(eg for leakages control/prevention, preventing overfills, controlling vent
emissions, on relief valves/bursting discs, spill procedures/collection, resealing
of contaminated drums/containers and decontamination equipment, cleaning of
control equipment.)
d) Management systems for carcinogens:
•
Containment strategy
(selection/management, design process, operational, maintenance,
monitoring/inspection)
• Written operating procedures
(based on hazard rating and containment plan, appropriate equipment, procedures,
cleaning in place procedures, etc)
•
Training/ refresher
(formal procedures/ on the job training/documentary records/ programmes
related to risk/ programmes for contractors visitors/ qualification
requirements etc.)
•
Incident reporting/actions
( eg hose/pipework/ flange leakages /breakdowns of control
equipment/adverse monitoring results)
e) Operator exposure potential
•
Who may be exposed, patterns of exposure
( criteria for judging acceptable control, quantification /assessment/results, thresholds
set, air sampling, biological monitoring, health surveillance, illness recording)
•
Any evidence of ill-health
(eg Surveillance programmes, patterns)
f) Support activities of relevance:
(eg maintenance /quality control sampling/ contractor and visitor control arrangements)
39
g) Control techniques:
• Engineering-
(i.e. closed system handling, dry couplings, enclosures, ventilation, VOC
recovery from vents, monitoring of liquid levels, bottom loading, sensing
devices for movement on mobile tankers, interlock barriers).
(Performance validation of eg valves, pumps, compressors, flanges, safety
valves
Maintenance and testing with records, weekly/ checks by operators, spares
readily available, adequate disposal arrangements for contaminated materials,
bungs, packaging, valve seals etc)
•
PPE
(eg types in use, glove, visors, respirators overalls/coveralls/chemical
suits/footwear, selection criteria re contact time, breakthrough,
permeation, degradation, training, use, cleaning/decontamination of
PPE, testing etc.)
• Welfare
Procedures
for
cleaning
monitoring/supervision,
and
decontamination,
facilities,
• Public risks prevention
(eg from transport, storage, disposal contaminated materials, wastes)
h) Validation of all the above:
•
Design /Operation/Auditing programme
(eg on-going operator inspections, routine audits of procedures, professional
external reviews of operations)
•
Results and record keeping of audit programmes
( eg how are they recorded and acted upon record systems and procedures for
maintenance /monitoring of control devices)
i) ‘ Site’ visit to review activities in practice:
•
Process/Plant/Equipment /Procedures
(eg General compliance with operating procedures/ training history/
incident actions/ record procedures etc.)
j) Visit report format:
•
General findings, conclusions and any ‘non-conformances’
•
Inspectors report to indicate summary details of visit and findings and any
follow up action that might be required.
40
Appendix 2 – revised version of questionnaire
Make introductions, thank for assistance, explain project, reporting process, scope of substances.
1. Company details
Name
Address
Number on site/shop floor
Brief company overview (other UK sites, other overseas sites)
Brief overview of activity on site
2. Substances of interest
Raw materials, intermediate chemicals generated, final products
Typical quantities involved (grammes, kilo, tonnes).
Is manufacturing on a batch or continuous basis ?
Where does company get chemical hazard information ?
3. Breakdown of tasks
Consider potential for operator exposures by all routes and engineering controls.
3.1 Delivery/transfer
How are chemicals delivered to site. How are they transferred into plant/storage. Is QC
sampling performed at this stage. (Top/bottom offloaded, vapour return lines, scrubber systems et,
overfill controls)
3.2 Routine plant operation
How are chemicals contained on site during routine use. Is containment breached for any
activity (including process sampling, making of manual additions). How is final product
discharged. What controls are applied at this stage ? Any other tasks with potential exposure
(filter cleaning )??
3.3 How is exposure controlled during routine maintenance activities (e.g line breaking, pump
maintenance, vessel entry).
3.4 Other control issues
Plant inspection (including maintenance/upgrading program)
Vessel overfill control
Use of bursting discs or other pressure relief systems
Emergency maintenance procedures
41
Spillage procedures (containment, clean-up, decontamination
4. Management systems for carcinogens:
4.1 Written procedures
What formal operating procedures exist for tasks with potential for chemical exposure. (Note –
please provide photocopies of procedures where possible). How is this information cascaded to
operators.
4.2 Health and safety training regime.
What induction training is provided for operators ? What refresher training is provided for
operators ? Is a formal safety induction provided for contractors working on-site ?
4.3 Is there a formal incident reporting scheme. How does this operate ?
4.4 Does the company provide a formal health surveillance scheme for workers with potential
chemical exposure. How does this operate ?
4.5 Internal inspection/auditing
Is there a regular internal program of safety inspections ? If so, how does this operate, are the
findings documented (Note – please provide examples from recent inspections, if they exist).
Is there a formal, higher level (or external) safety auditing procedure ?
4.6 Exposure monitoring
Has exposure monitoring ever been performed on workers with the potential for chemical
exposure ? How was monitoring performed ? Are records of monitoring maintained (Note –
please provide copies of monitoring results if possible) Is monitoring repeated periodically ?
5. PPE regime.
Consider higher level of protection required for maintenance, spillages – how does approach change, are
companies aware of HSE guidance on applying safety factor to breakthrough times, does SDS specify
correct glove material, as per ACOP ?
5.1 How is PPE selected ?
5.2 How is PPE issued and stored ?
5.3 How is re-usable PPE maintained. How is it decontaminated after use ?
Walk through assessment
Worker interview
42
Appendix 3 – template used for full visit report
HSL site visit report
Name of company – xxx
Address – xxx
Site contact – xxx
Date of visit – xxx
Overview
xxx
1. Hazardous substances used on the site
xxx
2. Hazardous substance - usage and control of exposure
xxx
3.1 Bulk transfer
xxx
3.2 Process sampling
xxx
3.3 Chemical spillage
xxx
3.4 Maintenance
xxx
3. Control strategies for other chemicals.
xxx
5. Other issues
5.1 Air monitoring
xxx
5.2 Health surveillance
xxx
5.3 Operator training
43
xxx
5.4 PPE regime
xxx.
6. General discussion.
xxx
44
Appendix 4 – template used for summary visit report.
Substance information
Usage pattern
Method of delivery/storage
Method of transfer into usage
system
Controls during usage
Process sampling strategy
Method of transfer of final
product
Written operating procedures
to cover all tasks with
exposure potential ?
Operator training regime
PPE regime
General
comments
and
specific weaknesses
45
Appendix 5 – Matrix 1 – use of control hardware
Site ID
Substance(s) in use
Activity
1. Chemical delivery
1.1 Tanker offloading – spillage
control
1.2 Tanker offloading – emission
control
2
Raw material – quality
sampling
3 Bulk container transfer
4 Containment during normal use
Frequency
Not at Sometall
imes
Use of dry break couplings
Rinsing of lines before breaking
Blowing dry of lines before breaking
Overfill control - alarm
Overfill control – cut out
Drive-away protection
Bottom offloaded
Sealed transfer system with return lines
Tanker and storage tank vented through scrubber
Tanker and storage tank vented to atmosphere
No sampling
In-line sampling
Sealed sampling system
Open sampling system with controls
Open sampling system without controls
Sealed system
Open system with engineering control
Open system without engineering control
No planned breaches
Containment broken only for sampling
Containment broken for other activities
Open to atmosphere
Emergency relief vents safely located
Vessels fitted with overfill alarms
Vessels fitted with overfill cut-out
46
Comments
Mostly
Always
Activity
5. QC sampling
6Product
discharge/decant
7.1 Tanker filling –
spillage control
7.2 Tanker filling –
emission control
8.1 Operator exposure
potential - inhalation
8.2 Operator exposure
potential - dermal
Frequency
Not at all
No sampling
In-line sampling
Sealed sampling system
Open sampling system with controls
Open sampling system without controls
Sealed system
Open system with engineering control
Open system without engineering control
Use of dry break couplings
Rinsing of lines before breaking
Blowing dry of lines before breaking
Overfill control - alarm
Overfill control – cut out
Drive-away protection
Bottom loaded
Sealed transfer system with return lines
Tanker and storage tank vented through scrubber
Tanker and storage tank vented to atmosphere
During tanker offloading
During bulk transfer
During normal use
During sampling
During product discharge
During tanker filling
During tanker offloading
During bulk transfer
During normal use
During sampling
During product discharge
During tanker filling
47
Comments
Sometimes
Mostly
Always
Appendix 6 - Matrix 2 – Control ‘software’
Site ID
Univar (Middlesbrough)
Subject
1. Hazard assessment
2. Management controls
Structured system of hazard assessment
Written SOPs to cover routine tasks
Written SOPs/’permit-to-work’ system for
planned non-routine tasks
Written SOPs/’permit-to-work’ system for
unplanned maintenance
Do written procedures cover all potential
exposure routes
3. Operator instruction
Formal operator induction training
Formal operator refresher training
Formal contractor safety induction
4. PPE - gloves
Systematic selection process
Systematic control in-use
Specific glove training
Disposed after single use
Effective decontamination procedure
High dependence in routine operation
High dependence in non-routine operation
Systematic selection process
Systematic control in-use
Specific PPE training
Disposed after single use
Effective decontamination procedure
High dependence in routine operation
High dependence in non routine operation
5.PPE - other
Frequency
Not at all
48
Comments
Sometimes
Mostly
X
Always
Subject
Frequency
Not at Sometall
imes
6.RPE
Systematic selection process
Systematic control in-use
Effective RPE training
Disposed after single use
Effective decontamination procedure
Fit testing
High dependence in routine operation
High dependence in non routine operation
7.Exposure monitoring
Suitable methodology
Monitoring program covers all relevant tasks
Task specific exposures monitored
Results saved appropriately
Exposure standards
Results acted upon if necessary
Monitoring repeated at appropriate intervals
Biological monitoring
8.Miscellaneous
Structured health surveillance program
Structured incident reporting system
Structured plant inspection and maintenance
program
Structured inspection system for control systems
Appointment of appropriately
qualified/experienced health and safety managers
49
Comments
Mostly
Always
Appendix 7 – key to matrices
For both matrices, the ‘comments’ column may be used as appropriate to add any additional
information. Generally, comments should be kept to a minimum, as these matrices will always
accompany a full narrative report.
Matrix 1 – Hardware
This relates to specific control hardware used for the substances discussed during the visit. If
more than 1 substance was discussed, then a separate matrix is required for each.
Company ID – full name of company, plus location of site visited
Substance(s) in use – all substances which that particular matrix refers to, include R-phrases.
N.B – some visits may generate more than 1 matrix, if information is collected on control of
exposure to several substances.
Section 1 – Chemical delivery –. If there are no CMRs used at the beginning of the process, this
section is not applicable (N/A) and should not be completed. This section relates to bulk
offloading of CMRs into storage/usage system. This may be from road tankers, rail cars or ships
(which one should be specified in comments box).
Section 1.1 relates to ‘spillage control’, i.e maintaining bulk containment. Section 1.2 relates to
emission control, i.e containment of vapour/dust during offloading.
‘Use of dry break couplings’ – are commercially manufactured dry break couplings used ?
‘Rinsing of lines before breaking’ – are lines rinsed with solvent (including water) after transfer
? (Note – use comments column to indicate which solvent is used, and where they are rinsed to.
‘Blowing dry of lines before breaking’ – are transfer lines blown dry before connections are
broken ?
‘Overfill control - alarm’ – is transfer system fitted with overfill alarm ?
‘Overfill control – cut-out’ – is transfer system fitted with automatic cut out to prevent overfill ?
‘Drive-away protection’ – is there a formal drive-away protection system in place ?
‘Bottom offloaded’ – are tankers bottom offloaded ?
‘Sealed transfer system with return lines’ – are return lines (usually vapour return lines) used to
maintain containment and balance pressures in road tanker and site storage tank during transfer.
‘Tanker and storage tank vented through scrubber’ – if the system is vented (return lines not
used), are suitable scrubbing systems fitted, where required
‘Tanker and storage line vented to atmosphere’ – is either the road tanker, or site storage tank,
or both, directly vented to the atmosphere during transfer.
2. Raw material – quality sampling – this is relevant irrespective of how the product is
delivered. The sampling system may be different to that used for taking QC samples from the
process. A ‘sealed sampling system’ is one where a sample is removed with no potential for
operator exposure. For ‘open system with controls’, the controls may be local exhaust
50
ventilation, or some form of containment system which leaves some potential for operator
exposure (either dermal or inhalation).
3. Bulk container transfer – this section is only relevant where the CMR is delivered to the site
in semi-bulk containers such as IBCs or drums. A ‘sealed’ system would be a permanent
connection to the container. Open system with engineering control indicates that the container is
open to atmosphere whilst it is emptied, but some form of LEV system is used. ‘Open system
without engineering control’ indicates that no controls (other than RPE, if used) are employed
during emptying of semi-bulk containers.
4. Containment during normal usage. The first 4 lines of this section are to be use to describe
the degree of containment during normal usage, hence any 3 of these 4 lines will be N/A each
time the matrix is completed. ‘Containment broken for other reasons’ – these include the
making of manual additions.
‘Emergency relief vents safely located’ – this relates to what happens if safety vents (such as
bursting discs) are activated in the event of a malfunction, such as a vessel overpressure or over
temperature. Do these vent to a safe area, such as a dedicated dump/waste/quench tank.
‘Vessels fitted with overfill alarm’ – is overfill alarm system fitted to all receiving vessels ?
‘Vessels fitted with overfill cut-out’ is auto shut down system fitted to all receiving vessels ?
5. QC sampling – this refers to the taking of process samples during the reaction stage, and of
the final product. See section 2 (above) for detail on description of sampling methods.
6. Product discharge – this section refers to the transfer of final product into semi-bulk, and
hence is only relevant on sites where this is performed. See section 3 (above) for description of
the different systems. Also in comments column give detail on the CMR content in the final
product, this may vary from ppm levels (such as residual monomer) to 100 % v/v (where the
CMR is the actual product).
7. Tanker filling. This section refers to loading of bulk tankers (road, rail or ship) for export
form site, and is only relevant where CMR is exported from site. For fuller description of the
headings used in this section, see section 1 (above).
8. Operator exposure potential – this section requires a judgement to be made regarding the
potential for operator exposure by both the dermal and inhalation route, at specific stages of the
process. The ‘not at all’ option should only be used where there is zero potential for exposure
(i.e total containment during that specific task. Conversely, for tasks where exposure routinely
occurs, the ‘always’ column should be used. In between these two extremes, ‘sometimes’ and
‘mostly’ can be used to describe the degree of exposure control applied. The use of PPE should
be discounted when considering this section i.e if RPE is the only protection against inhalation
exposure, then record this as if exposure does occur, if gloves are the only barrier against hand
exposure, and they are routinely contaminated by the task then record this as actual exposure.
Matrix 2 – Software
1. Hazard assessment – is there a structured system in place for assessing the toxicological
hazards of new substances when these are brought onto the site. ‘Not at all’ indicates a total
absence of any system for identifying toxic hazards, ‘Always’ can be used to indicate a formal,
structured system, with ‘sometimes’ and ‘mostly’ used with judgement to describe systems
between these two extremes.
51
2. Management controls
‘Written SOPs to cover routine tasks’ – are there written procedures to cover all routine plant
operations
‘Written SOPs/permit-to-work’ system to cover planned non-routine tasks’ –planned, non
routine tasks are, for example, maintenance and cleaning activities. Use comments column to
indicate if permit-to work is preferred option here.
‘Written SOPs/permit-to-work system to cover unplanned maintenance’ – unplanned events
are, for example, spillages or breakdowns. Use comments column to indicate if permit-to-work
system is preferred option here.
‘Do written procedures cover all potential exposure routes’ – a judgement is to be made here.
Based on the nature of the tasks and the physical properties of the substance, consider where in
the task there is potential for exposure. Are these potential exposures flagged up in the written
procedure ?
3. Operator instruction
‘Formal operator induction training’ – is structured, recorded, validated induction training given
to new operators, before they are allowed to work on the plant.
‘Formal operator refresher training’ – is a structured, recorded, validated refresher training
provided for plant operators.
‘Formal contractor safety induction’ – are contractors given a formal safety induction prior to
commencing work.
4. PPE gloves
This section deals specifically with gloves used for chemical protection. The comments should
be used to add relevant information not covered in the questions.
‘Systematic selection process’ – is chemical compatability considered when selecting glove
material
‘Specific glove training’ – including instruction on donning/doffing/disposal
‘Effective decontamination procedure’ – only applicable where gloves are re-used.
‘High dependance in normal use’ – is the glove use as primary control measure, i.e are there
tasks where gloves provide the only barrier against dermal exposure
‘High dependance in non-routine use’– would gloves be used as primary control for planned,
non-routine activities (such as cleaning and planned maintenance but not including emergencies
such as spillages).
5. PPE – other
This section deals specifically with PPE used for chemical protection with the exception of
gloves and RPE, i.e chemical protective clothing such as oversuits
For a description of the sub headings see section 4 (above).
52
6. RPE
This section deals specifically with RPE. Generally, for description of sub headings see section
4 (above).
‘Systematic selection process’ – is RPE selected on case-by case basis for individual chemicals.
If filtered RPE is used, are correct filters fitted.
‘Systematic control in-use’ – this question should consider storage, maintenance and
examination, including filter changing where appropriate.
7. Exposure monitoring
‘Suitable methodology’ – this is defined as personal exposure monitoring, using a validated
method.
‘Monitoring program covers all relevant tasks’ – is sampling performed for all jobs with
exposure potential ?
‘Task specific exposures monitored’ – has TSE monitoring, using personal sampling, been
performed. Only use ‘always’ if this has been done for ALL tasks with exposure potential.
‘Exposure standards’ – are results referenced against exposure standards. Are these HSE OELs
or in-house limits ?
‘Results acted upon if necessary’ – is corrective action taken for ‘high results’ (the comments
box will be required to elaborate on this)
‘Biological monitoring’ – is some form of BM (generally urine sampling, but may infrequently
entail blood or breath sampling) used to assess total body dose.
8. Miscellaneous
This section deals with other significant health and safety management systems not covered by
the above categories. For the first 4 items in this section, ‘Not at all’ indicates total absence of a
structured system in that area, ‘Always’ is used to describe comprehensive system covering all
aspects, with ‘sometimes’ and ‘mostly’ used with judgement to describe situations in between.
‘Appointment of appropriately qualified/experienced health and safety managers’ – only use
‘always’ here if there is a full time, competent occupational hygienist on the site.
53
Appendix 8 – summary of exposure monitoring data obtained.
This document summarises the exposure monitoring data, mainly personal sampling of
inhalation exposure, collected from the sites visited during the project. Unless specified
otherwise, the site has performed no biological monitoring.
Site 1
Benzyl chloride handling - good quality task specific exposure data, including OH report and
individual data points. Benzyl chloride exposures during drum emptying (done in laminar flow
booth) range from 0.08 ppm to 0.13 ppm, with exposure periods of 90 to 120 minutes. Highest
result 0.21 ppm (135 minute exposure time) included charging benzyl chloride from drums and
discharging product containing approx. 1% benzyl chloride into drums (also done in laminar
flow booth).
Site 2
Handling acrylamide, acrylonitrile and butadiene, plus dichloromethane is a separate process.
Comprehensive program of acrylamide monitoring performed in 1992, but not repeated since.
Basic contextual information recorded, plus individual data points. Measurement technique is
questionable, it ignores the possibility of particulate phase acrylamide - which is a solid at STP.
Task specific data for road tanker offloading, 2 results, <0.002 mg/m3 and 0.003 mg/m3, over
approx 100 minute period. Task specific exposures during product filtering, 4 results, highest
0.003mg/m3 over 35 minutes. Fourteen full shift results, 13 not detected (<0.002 mg/m3), one
0.003 mg/m3.
Comprehensive, ongoing program of dichloromethane monitoring, individual data points, with
basic contextual information recorded. Measurement technique OK. Data supplied for period
1985 to 1996. 8 hour TWA exposures (138 results) generally below 10 ppm, occasional result in
range 10 to 20 ppm, one exceptional result of 54.8 ppm, this operator spent significant amount
of shift on an unusual maintenance duty. Limited number of task specific results (8), highest
443 ppm, insufficient contextual information for thee to be useful.
Site 3
Handling acrylamide. Ongoing monitoring program for acrylamide (MEL 0.3 mg/m3). Approx
50 data points supplied, covering period 1993 to 2000, virtually no contextual information
recorded, measurement method questionable, it ignores possibility of particulate phase
acrylamide (which is a solid at STP). Only 2 results over 0.1 mg/m3 in the data supplied, highest
0.15 mg/m3.
Site 4
Handling hexavalent chromium compounds, dichloromethane, hydroquinone. Ongoing
monitoring program (for various solvents), results recorded but not in any clear format. No
results obtained from this site.
Site 5
Handling formaldehyde. Ongoing monitoring program, using long term diffusive stain tube
(formaldehyde), in conjunction with direct reading instrument - results studied during site visit,
54
vast majority < 0.1 ppm (8 hour TWA), very little contextual information recorded - no results
taken from site.
Site 6
Handling lead chromates, no monitoring done at any time.
Site 7
Handling dimethyl sulphate and acrylamide - the company have never monitored for either.
Site 8
Handling ethylene oxide - very occasional monitoring, no contextual information recorded, 2
data points supplied. One full shift of <0.02 ppm,, one task specific during tanker offload of
<0.7 ppm. Also handle benzyl chloride and dimethyl sulphate - no monitoring for these. Some
results also obtained for solvent exposure (xylene/toluene) - again, no contextual information,
all below 1.5 ppm.
Site 9
Handling dimethyl sulphate (MEL 0.05 ppm), other CMRs also handled. No monitoring done at
time of visit - 5 task specific data points subsequently supplied for road tanker offloading (full
air fed suit worn for this). Contextual information also supplied, exposures range from <0.01
ppm to 0.07 ppm over periods of 85 to 105 minutes.
Site 10
Handle nitrobenzene - OES 5.1 mg/m3 (plus aniline and lower toxicity stuff) - monitoring
survey conducted in 1994, including biological monitoring, methodology looks OK, individual
data points supplied but no contextual information recorded. Twenty eight results supplied (all 8
hour TWA) - range from not detected (LOD not quoted) to 0.625 mg/m3.
Further air monitoring in 1995 has very basic contextual info. Two task specific results recorded
for maintenance task, 0.42 mg/m3 and 0.63 mg/m3 over approx. 3 hour period.
Further task specific monitoring in 2000, again very basic contextual info, exposures measured
during drum filling with nitrobenzene contaminated residues. Results of 0.43 mg/m3 and 0.86
mg/m3 (58 minute exposure), and 1.04 mg/m3 and 0.83 mg/m3 (48 minute exposure).
One task specific result from 2002, exposure of 1.25 mg/m3 for 20 minutes during maintenance
(filter cleaning) task.
Site 11
Handle vinyl chloride monomer - perform frequent personal monitoring, methodology good.
267 8 hour TWA results from 2001-02 were supplied in summary only supplied with no
contextual info. For these data, only 2 results exceeded the MEL, and only one other exceeded
25% of the MEL. (MEL refers to 7 ppm, which was in place at the time of sampling - this has
been reduced to 3 ppm subsequently).
Site 12
Handle formaldehyde - the only monitoring they have done is spot readings with stain tubes, no
personal monitoring done at any stage.
55
Site 13
Handle benzene contaminated fluids - some monitoring done for benzene, plus other substances
- 2 recent data points supplied, 8 hour TWA results of 0.03 ppm and <0.03 ppm. No contextual
information recorded.
Site 14
Handle dimethyl sulphate and benzyl chloride, no personal monitoring for either. Use an
(uncalibrated) instrument for taking spot measurements of DMS.
Site 15
Handle formaldehyde and dichloromethane - no personal monitoring for either, some ad-hoc use
of stain tubes and (uncalibrated) instruments.
Site 16
Manufacture hexavalent chrome compounds (from ore). Extensive, ongoing air monitoring
program using well validated methodology, all results stored on in-house database, 11,000
personal monitoring results held on record. Not practical to obtain a copy of this database
during the visit. Work to an in house limit of 30% of MEL, i.e 0.015 mg/m3. Very few results
exceed this. Some use of task specific monitoring, but no data supplied. Some BM as one off
exercise.
Site 17
Handle o-toluidine, plus some other CMRs at times. No monitoring performed. This company
rely on clinical diagnosis of cyanosis to indicate over exposure ! No BM (other than cyanosis
testing, in extreme circumstances).
Site 18
Handle dimethyl sulphate, no personal monitoring performed. Some monitoring was done by
HSL around 6 years ago as part of development of MDHS for DMS - this was almost
exclusively static monitoring, a single task specific personal sample was taken during making of
manual additions to a reactor via an open manhole, result 0.018 ppm, very little contextual info
to accompany it.
Site 19
Handle arsenic salts. Ongoing program of air sampling (methodology OK) and urinary
monitoring (methodology poor, method does not distinguish dietary intake from occupational
intake, dietary can be highly significant, methods are available which make this differentiation)
- results supplied for 52 personal air samples taken from Jan 01 to September 03, all long term
(full shift), range from 2 to 54 µg/m3, with a significant proportion on range 10 to 40 µg/m3 (cf
MEL 100 µg/m3) - no contextual info with results, no task specific data supplied. Extensive
BM, but questionable methodology.
Site 20
Handle dimethyl sulphate and dimethyl formamide. Some monitoring done, but not much. Two
monitoring exercises in past 4 years, only task specific monitoring performed, one exercise
56
during a maintenance task, other whilst charging DMS to plant from kegs in laminar flow booth,
all results <0.005 ppm (cf 8 hour MEL 0.05 ppm).
Site 21
Handling butadiene, acrylonitrile and acrylamide. Limited (n=6) recent full shift results for
butadiene (and toluene), no contextual info. Butadiene results range from 0.15 mg/m3 to 0.82
mg/m3 (MEL = 10 ppm, 22 mg/m3). Some other results which are impossible to interpret. No
data supplied for acrylamide or acrylonitrile.
Site 22
Extensive monitoring program for ethylene dibromide, results discussed during visit but no
copies supplied. Results showed a clear reduction in exposures over the period 1985 to 1990,
achieved by an extensive, systematic study of all potential exposure sources. Where any
exposure source was identified, improvements to hardware or working practices were made.
Monitoring since 1990 has continued on a reduced basis, generally almost all results have been
below 0.5 mg/m3 over the period 1990 to 2003.
Site 23
Handling cyclohexane, cyclohexanol and cyclohexanone, substantial number of results supplied
for each. All 8 hour TWA, no contextual info, all from routine monitoring performed in 2002
and 2003. Results generally below 10% of relevant OES.
Site 24
Handling chromic acid (hexavalent chromium). Two task specific results supplied for mixer
operation. One result of <0.026 mg/m3 (28 minute sample), one result of <0.005 mg/m3 (90
minute sample, taken by HSL as part of a recent project, biological monitoring data available to
accompany this result).
Site 25
Handling mixtures containing benzene (up to 60%). No meaningful monitoring data available
Site 26
Handling ethylene oxide. Limited quantity of good quality task specific data supplied for tanker
offloading and maintenance. Data obtained using direct reading instruments, logging and
mounted in breathing zone. 4 task specific data points supplied for tanker offloading. Peaks to
22 ppm, average exposures over offloading period to 0.7 ppm, over periods of around 1.5 to 2
hours. 4 task specific data points for maintenance activity, peaks to 74 ppm, average exposures
as high as 3.24 ppm over 80 minute measurement period. Operators report occasional peaks to
200 ppm when breaking into equipment which cannot be fully drained and purged. Studying
sites monitoring data during visit revealed a single breach of the MEL in past 8 years, a result
of a peak exposure of >300 ppm as a result of incorrect breaking of a road tanker coupling,
resulting in 8 hour TWA of 14 ppm.
Site 27
Handling ethylene oxide. Monitoring data for 2003 supplied. 25 full shift data points. 19 results
<0.05 ppm, other results of 0.18 ppm (general duties) 0.33 ppm (no job description provided)
57
0.89 ppm (general duties, including QC sampling), 0.63 ppm, 1.46 ppm (both maintenance
activities) and 0.27 ppm (road tanker loading). No task specific monitoring.
Site 28
Handling hydrazine (as hydrate, 64% v/v aqueous solution). MEL 0.02 ppm (8 hour TWA). No
personal monitoring data. Only results from uncalibrated, hand held, spot reading instrument
used regularly around drumming operation. Significant proportion of results exceed 1 ppm, with
130 ppm highest recorded.
Site 29
Handling benzyl chloride. No monitoring conducted at any time whatsoever.
Site 30
Handling benzene (MEL 1ppm) and propylene oxide (MEL 5 ppm). The only monitoring
performed at this site was with spot reading stain tubes, held approximately in the operators
breathing zone. Sample of recent results supplied for benzene - tube readings to 2 ppm during
road tanker loading (splash loading with LEV) under normal conditions, results around 10 ppm
when LEV system not functioning correctly. Results to 12 ppm when disconnecting ship-shore
connection after ship loading.
Site 31
Handling vinyl chloride monomer (VCM). Extensive, ongoing program for VCM monitoring,
focussing on full shift. Results generally N.D (<0.1 ppm), occasionally higher and occasional
breach of 3 ppm (around once per year from around 300 samples). Some task specific
monitoring, and some use of direct reading instrument, but data not supplied.
Site 32
Handling trichloroethylene, also VCM.
Trichloroethylene - extensive personal monitoring program using full shift monitoring, results
supplied going back several years. On manufacturing plant, in excess of 2,000 results supplied,
one breach of MEL (1029 ppm). 750 full shift results supplied from shipping plant. These
indicate frequent breaches of MEL during barrel filling,around 5% of results exceed MEL. This
activity ceased in 1999, no breaches of MEL since that time. No task specific data for this
substance.
Regular (full shift) monitoring on VCM road tanker loading operation., plus task specific when
full shift indicate problems, including DRI (Multirae) to identify peaks and problems. Around
300 full shift samples per year in VCM tanker loading area, over past 5 years >99% of
exposures have been <MEL, vast majority of these <0.5MEL. Occasional high result, 2
examples provided. One result of 2.6 ppm as a result of faulty road tanker valves. This lead to
an investigation, using direct reading instrument, occasional peaks in excess of 300 ppm VCM
during loading. One 8 hour TWA result of 5.9 ppm, a result of inadvertant release due to
operator error.
Site 33
58
Handle benzene, as part of oil refining process. Extensive full shift data supplied for period
1996 to 2003. Majority of 8 hour TWA exposures below 1 ppm (only 14 results from 747
exceeded 1 ppm). Some use of task specific monitoring, but very guarded about results and
would not release to HSE.
Site 34
Handle aniline, acrylonitrile and VCM. Task specific monitoring done for acrylonitrile in 1994,
during road tanker loading operation. 14 results supplied, exposures range from 0.3 to 9.71 ppm,
over periods ranging from 30 to 90 minutes. ( 8 hour TWA MEL 2 ppm). Vapour return line
and dry break couplings probably (not certain) used at the time this exercise was performed.
VCM exposures measured in operator’s breathing zone during breaking of ship/shore
connection after ship offload, results as high as 1500 ppm, more typically around 60 ppm.
Offload hose blown clear prior to disconnection, plus AX RPE worn for this task. VCM 8 hour
MEL 3 ppm.
Site 35
Handling methyl glycol, methyl di-glycol. 3 full shift data points for methyl glycol from 1990,
all below 2 ppm (cf MEL 5ppm), no monitoring since, no monitoring at all for MDG (no
regulatory limit for this).
Site 36
Handling benzene, nitrobenzene and aniline. Extensive (summarised) data supplied for full shift
monitoring. Mean annual benzene exposures for period 1991 to 2003 are all below 0.3 ppm, for
most years they are below 0.1 ppm. In most years in excess of 50 personal samples were taken,
most years no results in excess of 1 ppm have occurred. Mean annual aniline exposures over the
same period are all below 0.3 ppm, slightly less samples/year taken for this substance, again,
very few results exceed 1 ppm. Noitrobenzene results are possibly in error. The site have made a
switch to task specific monitoring in recent years, but no data was supplied for this. Some
biological monitoring historically, discontinued due to consistent low results.
Site 37
Handling acrylonitrile and acrylamide. Summary data only supplied with very little contextual
information. Acrylamide exposures measured extensively across the site, data supplied by
‘worker group’, with data supplied for 20 separate worker groups. No information is supplied
on the number of samples taken. No worker group has a mean exposure in excess of 0.1 mg/m3
(cf 8 hour TWA MEL of 0.03 mg/m3). Data for acrylonitrile is much more limited, and is
supplied for one worker group only, the mean exposure for this substance is 0.027 mg/m3 (cf 8
hour TWA MEL of 4.4 mg/m3).
Site 38
Handle benzene, as part of oil refining process. Limited exposure data supplied, all 8 hour TWA
results. Five samples from 2001, max exposure is 0.18 ppm, 14 samples for 2002, one result in
excess of 5 ppm, rest all substantially lower, mean exposure 0.43 ppm but this is upwardly
skewed by the single high result in the small data set.
Site 39
59
Handle benzene, as part of oil refining process. Approximately 300 8 hour TWA results
supplied, mainly from 2001 – 2002. Vast majority of results are <0.1 ppm, four 8 hour TWA
result exceeding 1 ppm, but none more than 2 ppm. Limited amount of task specific data
supplied. Personal sampling conducted over approx. 15 minutes during ship disconnection,
results variable, but highest is 37 ppm. Exposures during QC sampling measured at between 0.4
ppm (34 minute sample) to 2.1 ppm (19 minute sample), Some other task specific data also
supplied (around 90 results) for various activities, covering period 1994 to 2003, occasional
relatively high result, up to 7.5 ppm (6 minute sample) for a maintenance task. Some data also
supplied for butadiene, all task specific. Some very high results around 100 ppm and higher, up
to 1,000 ppm, over approx. 30 minutes during ship disconnection.
Site 40
Handle benzene, as part of oil refining process. 280 full shift monitoring results supplied for
period 1999 to 2002, only one of these exceeds 1ppm. Mean exposures are supplied, divided by
worker group, for 18 different groups. For 16 of these groups, mean exposures are below 0.1
ppm, highest mean exposures was for ‘janitors’, where mean was 0.27 ppm. Forty four ‘task
specific’ results supplied for the same period, all taken over 15 minutes, with no information
supplied on the actual duration of the task, the highest result from these is 0.31 ppm. Similar
data also supplied for 2003-2004, 140 full shift results, maximum result for these samples was
0.33 ppm, 8 ‘task specific’ results also supplied, some of these exceeded 4 ppm for ship
disconnection.
60
Appendix 9 – spreadsheet containing codified data on selected exposure controls
Key to spreadsheet
Column 1 – Site no.
Numerical site identifier.
Column 2 - Carc
What class of carcinogen is handled.(0=none, 1= cat 3 carc, 2 = Cat 1 or cat 2 carc.)
Column 3 - Repro
Are reprotoxins handled. (0=no, 1=yes)
Column 4 - Raw mat
Are CMRs used as raw materials. (0=no, 1=yes)
Column 5 - Bulk off
Are CMRs offloaded from bulk transport (road tankers/ships) (0=no, 1=yes).
Column 6 - Dry break
Are dry break couplings used for offloading bulk containers(0=no, 1=yes)
Column 7 – leak test
Are lines/couplings leak tested prior to offloading CMRs from bulk ? (0=no, 1=yes)
Column 8 – Vap ret
Are vapour return lines used for bulk offloading (0=no, 1=yes)
Column 9 – Line clear
Are lines cleared prior to uncoupling after offload ? (0=no, 1=yes)
Column 10 – RPE
Is RPE worn for uncoupling ? (0=no, 1=yes).
NB – columns 6 to 10 refer to bulk offloading activities, and will only contain data if there is a
positive response in column 5.
Column 11 – Semi-bulk in
Are CMR raw materials received in semi bulk containers, for example 1 tonne IBCs or drums of
varying capacity (0=CMRs not received in semi bulk containers, 1 = CMRs received in semi
bulk containers). NB - there will only be data in this column for sites using CMRs as raw
materials.
Column 12 – Eng con 1
This refers to the use of engineering controls during emptying of semi bulk containers (0=no
engineering control, 1= poor quality LEV, 2=good quality LEV, 3 = automated enclosed
system).
Column 13 – RPE 1
This column refers to the use of RPE for transferring CMR raw materials from semi bulk
containers (0=no RPE, 1= RPE worn).
61
NB – columns 12 & 13 refer to offloading CMRs from semi bulk containers. There will only be
data in these column for sites performing this activity.
Column 14 - Raw material sampling
This column refers to the sampling of CMR raw materials, if CMRs are not received as raw
materials then this column will be blank. (0= raw materials not sampled, 1= sealed/semi sealed
device, 2 = open device with LEV, 3 = open, no exposure control except PPE)
Column 15 - Proc sample.
This column refers to the taking of QC samples from the process (0=no sampling,
1=sealed/semi sealed sampling device, 2= open with engineering control., 3 = open with no
exposure control other than PPE, 4 – mixture of systems at different stages).
Column 16 – RPE sample
This column refers to the use of RPE for QC sampling (0= no RPE, 1= RPE worn). Where no
QC sampling is performed, this column is left blank.
Column 17 – CMR prod.
This refers to the final products produced from the site. (0=no CMR materials present in
finished products, 1=products contain CMR, in many cases these will be sites manufacturing
neat CMR materials)
Column 18 – Bulk load
This refers to the loading of CMR products onto bulk transport, either road tankers or ships
(0=no bulk loading, 1=bulk loading performed). For sites where the finished products contain
no CMRs this column is left blank.
Column 19 – Open fill
This refers to bulk loading methods, particularly the use of open filling of bulk containers (0=
no open filling, 1=open filling).
Column 20 – Dry break 1.
Are dry break coupling for filling bulk containers with CMRs (0=no, 1 = yes).
Column 21 – Leak test 1
Are lines/couplings leak tested prior to bulk loading CMRs? (0=no, 1=yes)
Column 22 – Vap ret 1
Is vapour return/recovery system used for bulk loading (0=no, 1=yes).
Column 23 – Line clear 1
Are loading lines and couplings blown clear prior to breaking couplings after bulk loading
CMRs (1= lines drained under gravity, 2= lines forcibly blown or rinsed clear).
Column 24 – RPE 2
Is RPE worn when uncoupling after bulk loading (0=no, 1=yes).
NB – columns 19 to 24 refer to loading CMR materials onto bulk transport containers (road
tankers or ships). These columns will only contain data for sites performing this activity.
Column 25 – Semi bulk out
62
Are CMR products loaded into semi bulk containers, for example 1 tonne IBCs or drums of
varying capacity (0=CMRs not received in semi bulk containers, 1 = CMRs received in semi
bulk containers). NB - there will only be data in this column for sites manufacturing/exporting
CMR products.
Column 26 – Eng con 2
This refers to the use of engineering controls during loading of CMR into semi bulk containers
(0=no engineering control, 1= poor quality LEV, 2=good quality LEV, 3 = automated enclosed
system).
Column 27 – RPE 3
Is RPE used during the loading of semi bulk containers (0=no, 1=yes).
NB – columns 26 7 27 refer to loading CMRs into semi bulk containers. There will only be data
in these columns for sites performing this activity.
Column 28 – Monitor
This refers to the quality of the site’s overall exposure monitoring program (0= no monitoring
performed ever, 1 = historical or insufficient monitoring only, 2 = current and adequate data
available, 3 = monitoring with direct reading instruments only, 4 monitoring with stain tubes
only).
Column 29 - TSE monitor
Has the site performed any task specific exposure monitoring (0=none, 1= some but flawed
methodology used, 2= good use of TSE monitoring)
63
64
8
REFERENCES
OH/2005/05. C. Keen - Control of benzene exposures at UK oil refineries, HSL report
OH/2005/05
HSE 1997 – ‘Confined Spaces Regulations 1997 - Approved Code of Practice, Regulations and
Guidance’
HSE 1998. Summary criteria for occupational exposure limits – EH64, C7 - 1,3-butadiene.
Control of Major Accident Hazards Regulations (COMAH) 1999. UK statutory
instrument 1999 743.
HSL report No. RAS/03/09 – ‘Loss of containment incident analysis’. Authors Alison Collins
and Deborah Keeley, HSL 2003.
HSE 2002 - ‘The Control of Substances Hazardous to Health (COSHH) Regulations –
Approved Code of Practice and Guidance’ HSE 2002.
HSE 1999 - ‘Health surveillance at work’, HS(G)61, HSE 1999.
HSE 2001. ‘Cost and effectiveness of chemical protective gloves for the workplace’. HSE
guidance note HS (G) 206, first published 2000
65
Site No. Carc Repro Raw mat
1
2
0
1
2
2
0
1
3
2
0
1
4
2
1
1
5
2
0
1
6
1
0
0
7
2
0
0
8
2
0
0
9
2
0
1
10
2
0
1
11
2
0
1
12
2
0
1
13
2
0
1
14
2
0
0
15
0
0
0
16
1
1
1
17
2
0
0
18
2
0
0
19
2
0
0
20
2
0
0
21
2
1
1
22
2
0
1
23
2
0
0
24
2
0
1
25
2
0
1
26
2
0
1
27
0
1
1
28
2
0
1
29
2
0
1
30
2
0
0
31
2
0
1
32
2
0
1
33
2
1
1
34
2
0
1
35
1
0
1
36
2
0
1
37
0
1
1
38
2
0
1
39
2
0
1
40
2
0
1
Bulk off
0
1
1
1
1
0
0
0
1
1
1
1
1
0
0
1
0
0
0
0
0
1
0
1
0
0
1
0
1
2
1
2
1
1
1
0
1
2
0
1
Dry break
0
0
0
0
1
0
0
0
0
0
Leak test
1
0
0
1
1
1
0
1
1
0
Vap ret
1
0
1
1
1
1
0
1
1
0
Line clear
1
2
1
2
2
2
2
2
2
2
RPE Semi bulk in Eng con1 RPE1 Raw mat sample
0
0
1
0
0
0
0
0
1
1
2
0
0
0
1
0
1
0
1
1
0
1
1
0
0
0
0
0
0
0
0
1
1
2
0
0
0
0
0
2
0
0
1
1
0
1
0
0
1
0
0
1
0
1
1
0
1
0
1
0
0
2
0
0
1
1
2
0
0
0
1
1
0
0
1
1
1
0
1
0
1
1
0
2
2
2
1
1
0
0
0
0
0
2
0
0
1
0
0
3
0
0
0
0
0
1
1
1
1
2
1
2
0
3
0
1
1
1
1
3
0
3
3
0
0
0
3
0
0
0
0
0
3
3
2
3
0
Process sample
0
3
3
4
3
3
4
4
4
1
3
2
0
3
3
3
4
4
4
3
4
3
1
0
2
3
3
2
3
3
3
3
1
4
3
3
3
2
3
3
RPE sample CMR prod. Bulk load Open fill Dry break 1
1
0
1
0
1
0
0
0
0
0
0
1
1
0
0
0
1
0
1
1
0
0
1
1
0
1
0
0
0
0
0
0
0
1
1
1
0
1
0
1
1
1
1
0
0
0
1
1
0
1
0
1
0
1
1
0
0
1
1
1
1
0
1
1
0
1
1
0
0
1
1
1
0
1
1
0
1
0
1
0
1
1
0
0
0
0
0
0
0
0
0
0
0
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
1
0
0
0
1
0
1
1
0
0
1
0
0
1
1
0
1
1
1
1
1
0
1
0
0
Leak test 1
Vap ret 1
Line clear 1
0
1
1
1
0
2
1
0
1
0
2
2
0
0
2
0
0
0
1
1
2
0
0
1
1
1
1
0
0
1
0
0
1
1
2
2
1
0
1
0
2
1
RPE 2 Semi bulk out Eng con 2 RPE 3 Monitor TSE monitor
0
0
0
0
0
2
0
2
2
0
0
0
0
3
1
0
1
0
0
2
1
0
0
2
1
3
2
2
0
0
0
2
1
1
0
2
0
0
0
2
0
4
1
0
1
3
0
2
1
0
2
2
0
2
2
0
0
0
0
0
0
2
2
2
0
0
0
2
2
0
0
1
0
1
1
1
3
1
1
1
1
1
1
0
2
2
1
2
1
2
2
0
0
0
0
1
2
0
2
1
0
0
0
1
0
4
1
1
0
2
1
0
1
0
1
1
1
3
1
1
1
1
2
1
1
2
0
1
0
1
0
1
1
0
1
0
0
2
0
0
0
0