The legal limits for occupational exposure to ~500 chemicals which are toxic by inhalation, or skin contact, are codified by OSHA in so-called Permissible Exposure Limit (PEL) values. Values are generally expressed in parts per million (or mg/m3) and can relate to short-term (15 min.), long-term (8 hour), or ceiling level exposures. PEL values for 50 common lab chemicals is also provided.
Exposure monitoring for any substance regulated by an OSHA standard will be performed if there is reason to believe that exposure levels exceed the action level, or Permissible Exposure Limit. The tasks of determining if exposure monitoring is required and performing or supervising exposure monitoring shall be the sole responsibility of EH&S. For “regulated carcinogens” (See Sec. II-11) EH&S does periodic reviews of usage practices and exposure monitoring to establish if there is reason to suspect there are exposures.