Understanding occupational exposure limits for benzene

Occupational exposure limits for benzene

Occupational exposure limits for benzene – EU Directive 2017/164/EU5 has introduced indicative occupational exposure limit values (IOELV).

These are health-based, non-binding values, derived from the most recent scientific data available and availability of measurement techniques. For any chemical agent for which an IOELV has been set at EU level, member States are required to establish a national occupational exposure limit (OEL) value. They are required to take into account the EU limit value, determining the nature of the national limit value in accordance with national legislation and current practice.

Member States are required to bring into force the laws, regulations and administrative provisions necessary to comply with this Directive by 21 August 2018 at the latest. IOELVs are established in relation to an 8 hour, time-weighted average (TWA) and, for certain chemical agents, to shorter reference periods, in general 15 minutes time-weighted average also known as short-term exposure limit values (STEL) to take account of the e ects arising from short-term exposure.

In the UK, the Health and Safety Executive (HSE) already publish OELs for a plethora of chemicals, including benzene, in a document known as EH406 Workplace Exposure Limits (WEL). They refer to a WEL value which means the same thing as an OEL.

The EU-wide 8 hour TWA for benzene is currently set at 1 part per million (ppm), equivalent to a concentration of 3.25mg/m3. However, the ECHA review shows that some member states have a significantly lower OEL value which probably indicates the ‘direction of travel’ for the OEL given that the World Health Organisation (WHO) says there is no safe level of exposure. It is also important to note the EU does not recommend an EU-wide benzene STEL value.

By contrast, legislation in the USA exists in the form of Federal Regulation 29 CFR part 19109 and while the legislative framework is less complex than the EU, the limit values vary according to dierent ‘agencies’ plus they all state a value for the STEL.