Workplace Exposure Limits

In 2005, a simpler occupational exposure limit system came into force. The old system of Maximum Exposure Limits (MELs) and Occupational Exposure Standards (OESs) was replaced with a single type of limit, known as the Workplace Exposure Limit (WEL). A WEL is the maximum concentration of an airborne substance averaged over a reference period that an employee may inhale. HSE guidance says that: “WELs should not be considered a hard and fast line between safe and unsafe”.

In 2011, the Workplace Exposure Limits were amended, resulting in 19 new or amended entries for substances, to comply with the European Commission’s Third Directive on Indicative Occupational Exposure Limit Values (2009/161/EU).