Occupational Exposure Limits (OELs) are normally averaged over an 8-hour workday and serve to protect against acute and chronic health effects.

Since 2013, the development of Workplace Environmental Exposure Levels (WEELs®) has been managed by the nonprofit organization Toxicology Excellence for Risk Assessment (TERA)​. Click on the OARS-WEEL web page to access all values. Values are listed as either AIHA (if developed before 2013) or OARS (if developed since then).