Occupational Alliance for Risk Science - Workplace Environmental Exposure Levels (WEEL)™

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.



bullet Click here for a pdf of the entire WEEL table.


bullet Click here for OARS-WEELs open for public comment.


bullet Click here for New or Revised OARS-WEELs.



*Absorbed rapidly through the skin in molten or heated liquid form in amounts that have caused rapid death in humans.

Worker exposure by all routes should be minimalized to the fullest extent possible.



AIHA - American Industrial Hygiene Association

DSEN - Potential for Dermal Sensitization

mg/m3 - milligrams per cubic meter

PPM - Parts Per Million

RSEN - Potential for Respiratory Sensitization

STEL - Short Term Exposure Limit

TWA - Time Weighted Average




For information related to AIHA values, please refer directly to http://www.aiha.org/get-involved/AIHAGuidelineFoundation/WEELs/Pages/default.aspx.


Inquiries regarding AIHA WEELs can be sent to AIHA Customer Service at 703-849-8888 or Infonet@aiha.org