Occupational exposure limits (OELs) are developed for protection of healthy workers; they are not intended for the general public, which includes sensitive populations such as infants, the elderly, or the infirm. OELs are based on repeated daily exposures over a working lifetime. They are normally averaged over an 8-hour workday and serve to protect against acute and chronic health effects.

In 2013 the development of Workplace Environmental Exposure Levels (WEELs) was transferred from AIHA to the Occupational Alliance for Risk Science (OARS) which is managed by Toxicology for Risk Assessment (TERA). AIHA will continue to provide a link to the OARS-WEEL webpage where the updated values are posted.​​