Physical Hazards
The following terms are frequently used when describing physical hazards associated with chemicals.
- Combustible liquid: Any liquid, or mixture with 1% or more of a liquid, with a flash point above 141°F, but below 200°F.
- Compressed gas: A gas or gas mixture with an absolute pressure exceeding 40 p.s.i. at 70°F, or exceeding 104 p.s.i. at 130°F, or a liquid having a vapor pressure exceeding 40 p.s.i. at 100°F as determined by ASTM D-232-72, a standard of the American Society of Testing and Materials.
- Explosive: A chemical that causes a sudden, almost instantaneous release of gas, pressure, and heat when subjected to sudden shock, high temperature, or pressure.
- Flammable:
- Aerosol: A material that can produce a flame or flashback from a valve opening.
- Gas: Any gas at ambient conditions that will cause a flammable mixture with air in concentrations of 13% or less.
- Liquid: Any liquid, or mixture with 1% or more of a liquid, with a flash point below 141°F.
- Solid: A material that is liable to cause fire through friction, contact with moisture, spontaneous reaction or retained heat, or which can be readily ignited and burns with enough persistence or violence to cause a serious health hazard.
- Organic peroxides: An organic compound with a bivalent O-O structure, which may be considered a peroxide derivative when one or both of the hydrogen atoms are replaced with an organic molecule. They present dangerous fire and explosion risks; many are strong oxidizers.
- Oxidizer: A chemical that initiates or supports combustion of other materials, causing fire by itself or by the release of oxygen or other gasses.
- Pyrophoric: A material that will ignite spontaneously in air at or below 130°F.
- Unstable: Any material which will vigorously decompose, polymerize, condense, or will become self-reactive when exposed to conditions of shock, pressure, or temperature.
