Where available, exposure limits as published by the Occupational Health and Safety Administration (OSHA) and the American Conference of Governmental Industrial Hygienists (ACGIH) have been included on the MSDS.

The OSHA Permissable Exposure Limit (PEL) is expressed as a time weighted average (TWA) and/or a ceiling concentration. The OSHA PEL is legally enforcable.

The ACGIH Threshold Limit Value (TLV) is expressed as a time weighted average (TWA), a short term exposure limit (STEL), and/or a ceiling concentration. The ACGIH TLV represents a health and safety recommendation.

Exposure Limit Definitions:

Ceiling	The exposure concentration that should not be exceeded, even instantaneously.
STEL	Short Term Exposure Limit: An employee's 15 minute TWA (see below) exposure which must not be exeeded in a work day.
TWA	Time Weighted Average: The average airborne exposure which shall not be exceeded in any 8 hour period during a 40 hour work week.
IDLH	Immediately Dangerous to Life or Health: This exposure limit represents a maximum concentration from which a person could escape within 30 minutes without impairing symptoms or any irreversible health effects. These levels were defined by the Standards Completion Program Committee.