Under OSHA, there are ~500 chemicals that have airborne chemical concentration limits known as Permissible Exposure Limits (PEL). Legally, you cannot be exposed above these limits. PELs are expressed in parts per million (or mg/m3) in air. PEL values can be for 15 minute or 8 hour exposure periods, or ceiling limits which should never be exceeded. A smaller table of PEL values for ~50 common lab chemicals is available.
EH&S does periodic quantitative exposure monitoring of lab operations to confirm acceptable exposure levels. Typically, if these materials are used in a fume hood and proper PPE is utilized, per this manual, then there is little reason to believe exposure levels are a concern. If exposure limits are exceeded, additional steps must be taken to reduce.
Of the 500 materials noted above, some are carcinogens which are further/highly regulated under separate OSHA safety standards. They are separated into two classes:
Regulated Carcinogens fall into a higher hazard class and have extensive additional OSHA requirements associated with them. There are 30 in this category, but the common ones found in the lab are formaldehyde, methylene chloride and benzene. It is important to effectively apply safety controls as the regulatory requirements for laboratories that exceed threshold values for these chemicals are very extensive.
Select Carcinogens are defined under the OSHA Lab Safety Standard as follows.
- Regulated Carcinogens (see above)
- Annual Report on Carcinogens published by the National Toxicology Program: all of the substances listed as "known to be carcinogens" and some listed as "reasonably anticipated to be carcinogens"
- International Agency for Research on Cancer: all of Group 1 "carcinogen to humans" materials; and some in Group 2A/B.