Environmental Health and Safety

MSDS Glossary

Environmental Toxicity
Information obtained as a result of conducting environmental testing designed to study the effects on aquatic and plant life.
U.S. Environmental Protection Agency.
Evaporation Rate
The rate at which a material will vaporize (evaporate) when compared to the known rate of vaporization of a standard material. The evaporation rate can be useful in evaluating the health and fire hazards of a material. The designated standard material is usually normal butyl acetate (NBUAC or n-BuAc), with a vaporization rate designated as 1.0. Vaporization rates of other solvents or materials are then classified as:

Fast evaporating if greater than 3.0.

  • Methyl Ethyl Ketone = 3.8
  • Acetone = 5.6
  • Hexane = 8.3

Medium evaporating if 0.8 to 3.0.

  • 190 proof (95%) Ethyl Alcohol = 1.4
  • VM&P Naphtha = 1.4
  • MIBK = 1.6

Slow evaporating if less than 0.8.

  • Xylene = 0.6
  • Isobutyl Alcohol = 0.6
  • Normal Butyl Alcohol = 0.4
  • Water = 0.3
  • Mineral Spirits = 0.1
A chemical that causes a sudden, almost instantaneous release of pressure, gas, and heat when subjected to sudden shock, pressure, or high temperature.
Exposure or Exposed
Exposure to a chemical occurs when the chemical is taken into the body through inhalation, ingestion, skin absorption, or any other means.
Exposure Limits
The concentration in workplace air of a chemical deemed the maximum acceptable. This means that most workers can be exposed at given levels or lower without harmful effects. Exposure limits in common use are:
  1. TLV-TWA: Threshold limit value - time-weighted average.
  2. STEL: Short-term exposure limit.
  3. 3. C: Ceiling value.
Extinguishing Media
The firefighting substance to be used to control a material in the event of a fire. It is usually identified by its generic name, such as fog, foam, water, etc.
Eye Protection
Recommended safety glasses, chemical splash goggles, or face shields to be used when handling a hazardous material.

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