There is not an OSHA PEL for every substance.
There are other exposure limit standards for chemicals from other organizations.
These are not enforceable by law, but are frequently based upon more recent evidence than
the PELs.
TLV -Threshold Limit Values.
Developed by the American Conference of Governmental Industrial Hygienists (ACGIH). The ACGIH is non-regulatory.
These values will frequently be found in MSDSs in addition to PELs.
Like most PELs, these are time weighted averages over an 8 hour day.
IDLH -Immediately Dangerous to Life or Health.
Exposure that poses an immediate threat of loss of life or immediate or delayed irreversible adverse effects on health that would prevent escape from a hazardous atmosphere.
Published by the National Institute of Occupational Safety and Health (NIOSH).
STEL -Short Term Exposure Limit.
15 Minute TWA that should not be exceeded at any time during a work day.
Ceiling Limit.
A limit that should never be exceeded at any time during a work day.
