INSTITUTE OF OCCUPATIONAL MEDICINE . Edinburgh . UK www.iom-world.org

Things just keep getting better

John CherrieI want

to

ELIMINATE

workplace

cancer

Summary…

• Exposures change over time, almost always decreasing

• What is the evidence for this? • Why are companies acting to

reduce exposures? • Is it true for all substances in

every country?

Exposure decreases over time…

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

Aerosols

Exposure decreases over time…

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

Gases and vapours

Exposure decreases over time…

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

Fibres

Let’s do a thought experiment…

• Start with a singe factory and follow it’s progress in controlling exposures over 10 years

• Repeat at different plants and see how the pattern builds up

Simulated exposure reduction at a plant

Five plants…

Ten plants…

25 plants…

Flour dust…

van Tongeren M et al. (2009) Trends of flour dust exposure in the United Kingdom, 1985–2003 Environ. Monit., 2009, 11, 1492 – 1497.

VCM levels in a English PVC plant

12

What changes?

• High pressure water jet cleaning

• Removal of VCM residues by stripping

• Improved general ventilation

• Use of scale inhibitors• Extraction on open

reactor vessels• Reduce leaks• Air monitor• Breathing Apparatus

Investigation of changes in exposure…

Galea KS et al. (2009) Trends in Wood Dust Inhalation Exposure in the UK, 1985–2005. Ann.Occ.Hyg.

Things changed…

What were the determinants of change?

• Economic• Market downturn – reduced production, less people• Improved efficiency – buying in ready-made

components

• Legislation• Environmental – achieve emissions targets• Health and safety – inspection visits, prosecution

• Safety culture• New owners – larger company• New managers – new ideas

What were the determinants of change?

Is this a “universal truth”!

Friesen MC et al. (2012) Combining a Job-Exposure Matrix with Exposure Measurements to Assess Occupational Exposure to Benzene in a Population Cohort in Shanghai, China. Ann Occup Hyg;56:80–91.

Benzene levels in China

Time trends in exposure…

Rubber - Crude Materials, Compounding and Mixing

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

1965

1970

1975

1980

1985

1990

1995

2000

2005

2010

mg/

m3

NetherlandsUnited KingdomPolandGermanySweden

Time trend

per year

UK : -6%

NL : -2%

PL : -6%

SW : -6%

GE : -7%

http://exasrub.iras.uu.nl/content.html

Agostini et al. Exposure to rubber process dust and fume since 1970s in the UK; influence of origin of measurement data. J. Environ. Monit. (2010) vol. 12 (5) pp. 1170

But not always!

Vermeulen R, Coble JB, Lubin JH, et al. The Diesel Exhaust in Miners Study: IV. Estimating Historical Exposures to Diesel Exhaust in Underground Non-metal Mining Facilities. Ann Occup Hyg 2010;54:774–88.

The Theory of Planned Behaviour

Behavioural beliefs

Attitude towards the behaviour

Normative beliefs

Subjective norms

Control beliefs

Perceived behavioural

control

Intention Behaviour

Actual behavioural

control

http://people.umass.edu/aizen/tpb.diag.html

Summary…

• In most situations exposure appears to decrease over time by between about 5% and 15% per annum

• Modestly effective controls implemented every three or four years is sufficient to explain these trends

• The most likely explanation is improving manufacturing efficiency

• There are some exceptions to the rule!