OEL

Occupational Health and Safety has always been at the heart of ESIG activities and Best Practice Guidelines and films on the safe handling of solvents can be found in our “resources” section. Occupational Exposure Limits (OEL) are essential to the protection of workers from health and safety risks due to exposure to airborne hazardous substances.

An OEL is an upper limit on the acceptable air concentration of a hazardous substance in workplace air for a particular substance or group of substances to which workers can be exposed throughout their working lifetime (for 8 hours per day, 5 days a week, for 40 years) without developing adverse health effects.

For over 60 years, regulatory organisations worldwide have been defining OELS. In the EU, the European Commissions is in charge of setting OELs following a scientific assessment and a consultation process, while a separate procedure can be in place in some Member States.

Information on existing OELs for HSPA and OSPA substances can be found in our overview documents:

• Hydrocarbon solvents registered under REACH – key data
• Oxygenated solvents registered under REACH – key data

GESTIS, the information system on hazardous substances of the German Social Accident Insurance, is a comprehensive database for chemical substances, which includes all the existing OELs. It includes their respective existing OEL.

Setting occupational exposure limits for hydrocarbon solvents is challenging since this type of solvents have complex  and variable hydrocarbon compositions . This means that the worker will inhale not only one but many types of hydrocarbons from the solvent at the same time. Some of these hydrocarbons are well characterized and have their own OELs, but for others,  information may be limited. Therefore, it is vital to define an OEL that takes into account all the relevant types of hydrocarbons and provides consistent occupational advice.

An approach that enables to calculate a unique OEL for each hydrocarbon solvent, based on relatively simple compositional information is needed.  Furthermore, it is not always possible to identify all of the components of hydrocarbon solvents, and most of the existing toxicology data relates to representative hydrocarbon solvents rather than their individual components.

Therefore, the Reciprocal Calculation Procedure – RCP- approach was developed by hydrocarbon solvent manufacturers in the United States and Europe, which  groups all hydrocarbons of similar physical, chemical and toxicological properties and assigns them a group guidance value or GGV, which covers existing OELs of representative hydrocarbons within a group. Using these GGV values in the RCP calculation ensures that the hydrocarbons in that group do not exceed their own individual OELs. In practice this means measuring a single OEL that reflects the solvent’s hydrocarbon composition.

Each GGV is supported by a series of toxicological studies including acute central nervous system effects that confirm that certain hydrocarbon constituents can be grouped together under three GGV and distinguish them from the Substance Specific Values or SSV.