The second presentation for the Singapore workshop and AIOH2013

1. What do you mean by
“eliminate”?
John Cherrie
INSTITUTE OF OCCUPATIONAL MEDICINE . Edinburgh . UK
www.iom-world.org

2. Summary…
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Elimination is a realistic possibility
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Elimination will be achieved when
workplace exposures are projected to
cause much less than 1% of all cancers
What needs to be done in
workplaces to reduce exposure?
How effective are the control
measures?

3. For communicable diseases…
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Control: The reduction of disease incidence.
prevalence, morbidity or mortality to a
locally acceptable level as a result of
deliberate efforts
Elimination of disease: Reduction to zero of
the incidence of a specified disease in a
defined geographical area as a result of
deliberate efforts
Eradication: Permanent reduction to zero of
the worldwide incidence of infection
Dowdle WR. (1996)The principles of disease elimination and eradication.
Bulletin of the World Health Organization; 76(Suppl 2): 22-25.

4. Elimination of occupational
cancer….
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…elimination of the disease as a public
health problem (i.e. reduction of cases
below what is considered to be a public
health risk)
What might be suitable target level for
occupational cancer?
Reduction of incidence of occupational
cancers to <<1% of all cancers?
Cherrie. We can eliminate occupational cancer from chemicals. Occupational
Medicine (2008) vol. 58 (5) pp. 314-315

5. We know what to do…
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Minimise emission, release and spread of substances
Take into account all relevant routes of exposure
Control exposure by measures that are
proportionate to the health risk
Choose the most effective and reliable control
options
Where needed provide suitable personal protective
equipment
Review regularly all elements of controls
Inform and train all employees
Ensure control measures does not increase overall
risk
http://www.hse.gov.uk/coshh/detail/goodpractice.htm

6. Range of possible control
measures…
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Elimination / substitution
Process modification
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Change form of materials
Reduce temperature
Isolation and segregation
General ventilation
Local ventilation
Maintenance, supervision, educati
on
Personal Protective Equipment

7. Exposure decreases over time…
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.

8. Effectiveness of substitution…
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Successes
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Bladder cancer in the rubber industry andβnaphthylamine
Toluene for benzene
However, substitutions are complex and
may have unexpected consequences
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use of citrus oil rather than
trichloroethylene, but…
d-limonene when oxidized presents risks as a
skin allergen

9. Exposure Control Efficacy Library
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Review of literature on the effectiveness of
enclosures, local ventilation and other
controls at source
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90 peer-reviewed papers
Wide variation in effectiveness
The data published since the ECEL report was
prepared broadly supports the original
analysis
Effectiveness in experimental or semiexperimental studies higher than other
situations
Fransman et al. Development and Evaluation of an Exposure Control Efficacy Library
(ECEL). Annals of Occupational Hygiene (2008) vol. 52 (7) pp. 567-575.

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

11. ECEL
Risk Management
Measure
n
LEV in general
LEV + enclosure
Integrated
Mobile
General ventilation
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

12. Assigned Protection Factors

13. Effectiveness of repiratory
protection…

14. Effectiveness of behavioural
interventions
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Results from a systematic review
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550 potentially relevant articles identified
10 were considered informative
Behavioural interventions had a
limited positive impact upon exposure
Not sufficient to just raise awareness
of risks and controls, need to equip
workers with skills to act on that
knowledge
Lunt JA, Sheffield D, Bell N, et al. (2011) Review of preventative behavioural
interventions for dermal and respiratory hazards. Occup Med (Lond);61:311–20.

15. Summary…
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Focus on a practical definition of
elimination is helpful
Strategies to control exposure are well
understood
The effectiveness of the approaches we
use is less well defined, but there is
sufficient data to know:
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Respirators > Fixed local ventilation > Mobile
local ventilation > General ventilation >
Behavioural controls
There is great variability in effectiveness
within a type of control measure