Exploring Exposure Limits: What do those numbers mean?

If you’ve ever attended safety training, you surely have heard the terms PEL, TLV, REL and STEL.  Do these letters really have a meaning or are they just a bunch of alphabet soup?  These acronyms all represent different occupational exposure limits (OELs) that are derived by different organizations.  An OEL is representative of the highest concentration a healthy worker can be exposed to for a full work week over the duration of their working life without experiencing an adverse effect.  Although similar, they each have a different goal and meaning.

Permissible Exposure Limit (PEL)

The Permissible Exposure Limit, or PEL, is the most widely known exposure limit.  This is the OSHA 8-hour time weighted average (TWA) exposure limit and is the only limit directly enforceable by regulation.  OSHA limits must be approved by Congress and take into account both health benefits and industry costs.  PELs are difficult to change because of the congressional approval required.  These […]