How are Occupational Exposure Limits determined?

The Occupational Exposure Limit (OEL) is a concentration level of a gas, vapour, aerosol, fibre or dust in the air in the workplace. This limit is determined according to the basic principle that the health of employees as well as that of their offspring must not be impaired.

Work programme

OELs are determined by the Minister or the State Secretary for Social Affairs and Employment. The OEL is substantiated in various ways. In Europe, this is done by the Scientific Committee for Occupational Exposure Limits (SCOEL) or the Risk Assessment Committee (RAC). In the Netherlands, it is the Health Council of the Netherlands that substantiates the OEL as regards health.

Carcinogenic and inhalable allergenic substances

No safe threshold level can be determined in the case of carcinogenic and inhalable allergenic substances, so risk levels are used. An OEL corresponding to a specific additional occupational risk was chosen. The OEL for carcinogenic and mutagenic substances is preferably set at what is called the target risk level: as low as possible.

At the concentration corresponding to the target risk, employees have an additional absolute risk of 4 out of 100,000 in 40 years of occupational exposure compared to the general population. The OEL for carcinogenic and mutagenic substances must never exceed what is called the prohibition risk level. At the prohibition risk level, employees have an additional absolute risk compared to the general population that is 100 times higher.

The SER performs a feasibility test. This investigation must show whether it is possible to keep the risk as low as possible through technical measures. The SER does this in consultation with employers’, employees’ and industry associations, as well as occupational health and safety professionals. On the basis of the investigation, the SER advises the Ministry of Social Affairs and Employment on an OEL for the substance in question.

As a rule, the OELs are reviewed every four years. Information on tests and investigations, and links to all the reports, can be found for each substance in the Occupational Exposure Limits for Hazardous Substances in the Workplace [Grenswaarden Gevaarlijke Stoffen op de Werkplek] database.