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Understanding Carcinogen Exposure

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The Health and Safety Executive's document EH40/2005 Workplace Exposure Limits (4th edition) identifies all known carcinogens and also details the legal exposure limits of over 500 common substances that are hazardous to health under the COSHH regulations.

Over recent years the workplace exposure limits (WEL’s) have been reduced for 11 existing carcinogens and 2 new substances have been classified as carcinogens.

Carcinogens cause occupational cancer as a result of work involving direct exposure to this classification of substance. There is usually a considerable amount of time (more than 10 years) between exposure to a carcinogen and the onset of any ill-health symptoms. Carcinogens occur in many forms - they can be solids, liquids, vapours, gases, or dusts. They can be breathed in, absorbed through the skin, or swallowed.

WELs are British occupational exposure limits which are set to help protect the health of workers. WELs are concentrations of hazardous substances in the air, averaged over a specified period of time, referred to as a time-weighted average (TWA).

In circumstances where work involves activities that lead to exposure to carcinogens, all reasonable efforts must be made to reduce exposure to levels as low as possible regardless of the measured exposure and the WEL level. For example, if exposure to hardwood dust was measured to be 1 mg/m3 and the legal WEL level  is 3mg/m3, action should still be taken to reduce the exposure to as low as possible. 

The following 11 existing carcinogens now have significantly reduced legal exposure limits (WEL’s), which are likely to require a review of existing COSHH risk assessments for applicable industries:

The following 2 substances have been classified as new carcinogens:

As a result of these exposure limit reduction and new classifications, it may be necessary to carry out interim or additional exposure monitoring to ensure you are meeting your legal obligations under the COSHH regulations.

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