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HSE Publishes Important Changes to Workplace Exposure Limits for Known Carcinogens


The Health and Safety Executive has issued a new version of the EH40/2005 Workplace Exposure Limits (4th edition) in January 2020. This document details the legal exposure limits of over 500 common substances that are hazardous to health under the COSHH regulations.

They have reduced the workplace exposure limits (WEL’s) of 11 existing carcinogens and classified 2 new substances as carcinogens.

Significantly, 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.

How can Euro Environmental help?

Our consultants are here to help you develop and implement monitoring strategies to identify if exposure limits are being exceeded in the workplace. 

Our team will advise appropriate measures to be taken to reduce the risk of exposure and ensure you comply with the Control of Substances Hazardous to Health Regulations.

Contact us today to arrange an initial workplace exposure assessment.


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