NAC National Advisory Committee on Acute Exposure Guideline Levels for Hazardous Substances
NIOSH National Institute for Occupational Safety and Health
NOAEL no observed adverse effect level
NOEL no observed effect level
NRC National Research Council
OEL occupational exposure limit
PEL permissible exposure limit
POD point of departure
ppb parts per billion
ppm parts per million
RD50 concentration of a substance that reduced the respiratory rate of test organisms by 50%
REL recommended exposure limit
SOP standing operating procedures
STEL short-term exposure limit
TLV Threshold Limit Value
TRI Toxics Release Inventory
TSD technical support document
TWA time-weighted average
μg microgram
UF uncertainty factor
URL uniform resource locator
WEEL workplace environmental exposure limit

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