Slides from a lecture given in Wuhan, China.

1. Occupational health risk
assessment and management
in Britain
John Cherrie
INSTITUTE OF OCCUPATIONAL MEDICINE . Edinburgh . UK
www.iom-world.org

2. Summary of presentation…
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Introduction
Risk, hazard and risk assessment
Legislation and practice in Britain
Responsibilities: government, industry and
workers
Control banding: COSHH Essentials
Modelling exposure
Exposure measurement
Control of exposure

3. Measurement
“When you can measure what you
are speaking about, and express it
in numbers, you know something
about it; but when you cannot
measure it, when you cannot
express it in numbers, your
knowledge is of a meager and
unsatisfactory kind…”
Lord Kelvin

4. More than 200 years…
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There has been concern in the UK about the
problems caused by poor working conditions
for more than 200 years
Around the 1850s:
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Ventilation in cotton mills
Local ventilation for grinding
In 1898 the first Medical
Inspector of Factories
was appointed
CARTER T. British Occupational Hygiene Practice 1720-1920.
Ann OccupHyg. 2004 Mar. 2;48(4):299–307.

5. Early experience in counting…
For more than 100 years we have counted
the number of lead poisoning cases in Britain

6. Not every risk decreases
Mesothelioma risk in Britain has increased over
recent years

7. The beginning of the science of
occupational hygiene…
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The invention of
the personal
sampling pump
Cherrie JW. (2003) The beginning of the science underpinning occupational
hygiene. Ann OccupHyg; 47: 179–85.

8. Mostly exposure is decreasing
Aerosols
Creely KS et al. (2007) Trends in inhalation exposure--a review of the data in
the published scientific literature. Ann OccupHyg.; 51(8): 665-678.

9. Mostly exposure is decreasing
Gases and
vapours
Creely KS et al. (2007) Trends in inhalation exposure--a review of the data in
the published scientific literature. Ann OccupHyg.; 51(8): 665-678.

10. Hazard and risk
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Hazard = type of harm,
e.g. asthma
Risk = the chance that
harm may occur in a
specific situation
Risk is managed in
practice by the
occupational exposure
limit (OEL) paradigm

11. Hazard and risk
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Hazard = type of harm,
e.g. asthma
Risk = the chance that
harm may occur in a
specific situation
Risk is managed in
practice by the
occupational exposure
limit (OEL) paradigm

12. The law in Britain…
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Health and Safety at Work Act
Regulations
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Control of substances hazardous to health
Noise at work
Ionising radiation
Approved Codes of Practice
Guidance
EU law
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Directives
Regulations, e.g. REACH

13. Responsibilities
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In law the employer has the
main duty to protect the
workers
Workers have a duty to
cooperate with employers
Government has
responsibility for promoting
health and safety
Government has
responsibility for enforcing
the law

14. Five steps for risk assessment
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Identify the hazards
Decide who might be harmed, and how
Evaluate the risks and whether the existing
precautions are adequate
Record your findings
Review your assessment

15. Simple risk evaluation
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Can I get rid of the hazard?
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Switch to a less hazardous material
Prevent access to the hazard using guards
or enclosures
Organise the work to reduce exposure
Improve ventilation
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Use personal protective equipment

16. Options for estimating risk
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Measurement of exposure level
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Can be expensive
Need to have access to the work situation
Requires several measurements to an accurate
assessment
Modeling of exposure level
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Low cost
Can be done before work starts
May not be accurate

17. Control banding
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A qualitative or semi-quantitative risk
assessment and management approach
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Grouping hazard, exposure and control options
In Britain for chemicals we use COSHH
Essentials
Question based online software tool
Output comprises a recommended approach
to control
Backed up with process and sector guidance

18. www.coshh-essentials.org.uk

20. Advice on…
Agriculture – farmer, Beauty treatments,
Baking and milling - flour dust, Car park
and bus depot, Brick and tile making –
silica, Cleaning services, Ceramics and
pottery – silica, Florist and greengrocer,
Construction – silica, Funeral
services, Engineering – abrasive blasting,
surface coating, Hospitality - pub, club and
restaurant, Engineering – metalworking
fluids, Leisure and sports, Foundries fume, silica, Maintenance and repair –
retail, Manufactured goods – silica, Motor
vehicles – spray painting, Microelectronics,
Motor vehicles - maintenance and repair,
Printing - ink, laminating adhesive, Pest
control, Printing – laminating, Warehouse,
Quarries – silica, Rubber making - dust,
fume, Slate making – silica,
Stonemasonry – silica, Welding and
cutting - fume, dust from abrasive blasting,
Woodwork - wood dust

21. Other exposure models…
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Advanced REACH Tool (ART)
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www.AdvancedREACHtool.com
An advanced modeling tool that provides an
estimate of the level of exposure for chemicals
Incorporates a means of combining
measurements with the model
Provides accurate exposure assessments
ECETOC TRA
Stoffenmanager
MEASE
EMKG-Expo-Tool

22. Exposure measurement
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Active samplers
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Passive samplers

23. Which is best?
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Active sampling ...
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gives the greatest sensitivity
greater versatility
more likely to be validated
Passive sampling ...
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more comfortable (acceptable)
less capital intensive
less attention need to get a valid sample

24. Direct reading instruments…
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Range of sensors
available for dusts,
gases and vapours
Cost ranges from
€100 to €3,000
Always require
calibration against a
more basic
measurement

25. Personal sampling…
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It’s very important to sample in the
breathing zone
Fixed location vs Personal sampling
Cherrie J (2003) The beginning of the science underpinning occupational hygiene.
Ann OccupHyg 47: 179–185.

26. Sampling duration…
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Variability in exposure results is a
function of the duration of the
measurement
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Short term samples are more variable
than long term samples.
Aim to measure for at least 6
hours, ideally for the whole work
shift

27. Group sampling…
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Select workers representative of
groups that are judged to have similar
exposure
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similarly exposed groups (SEGs)
Monitor as many workers as possible,
with some repeated over more than
one day
Assess within and between worker
variability

28. A new approach to compliance…
1. Divide the workforce into SEGs
2. Take 3 representative exposure measurements from
random workers in the SEG. If all <0.1xOEL then
compliance. If any result is >OEL then non-compliance
3. Take at least 6 more samples from the SEG, at least 2 per
worker from workers picked at random. Use all samples to
apply a test (70% confidence, that there is <5%
probability of any random exposure being >OEL)
4. Do an analysis of variance on all the results to establish
whether the between-worker variance is >0.2 x total
variance. If it is, then step 5 must be added.
5. Analyse the results to do an individual compliance test.
There should be <20% probability that any individual in
the SEG has >5% of exposures > OEL.
Available from… www.bohs.org/library/technical-publications/

29. Control…
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Traditionally, a hierarchy of control…
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High
Elimination
Substitution
Total enclosure
Segregation
Partial enclosure
Engineering controls, e.g. local ventilation
Local ventilation
Management initiatives
Low
Personal protective equipment

30. Exposure Control Efficacy Library
Fransman et al. Development and Evaluation of an Exposure Control Efficacy Library
(ECEL). Annals of Occupational Hygiene (2008) vol. 52 (7) pp. 567-575

31. ECEL
Risk Management
Measure
n
LEV in general
LEV + enclosure
Integrated
Mobile
General ventilation
RPE
Estimated
efficacy (%)
95% confidence
interval
280
82
78 to 84
9
86
69 to 94
133
87
84 to 90
4
61
-28 to 88
42
43
17 to 61
94 – 99.9

32. Major issues for the future?
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Education and training
Dermal exposure to chemicals
Combined exposure to different agents
Carcinogens
COPD
Asbestos
Nanomaterials
Behaviour and exposure
Small low-cost monitoring devices

33. Information…
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HSE website: www.hse.gov.uk
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HSE Books: books.hse.gov.uk
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Contains many links to free information
Most books are free to download, priced for
paper copies
COSHH Essentials: coshh-essentials.org.uk
BOHS:BOHS.org
Annals of
OccupHyg:annhyg.oxfordjournals.org
OHTA:www.ohlearning.com

34. Textbooks…
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Key British occupational hygiene textbooks

35. Questions?