Pictogram 4: Exploding Bomb, Explosives

Pictogram 4, the Exploding Bomb pictogram, identifies explosives. The HCS definition of an explosive is "a chemical that causes a sudden, almost instantaneous release of pressure, gas, and heat when subjected to sudden shock, pressure, or high temperature."

Explosives are unstable materials. OSHA classifies them as two types:

1. Explosives consisting of "material capable of supersonic reactions (detonation), for example, nitroglycerine and TNT."
2. Explosives consisting of "materials (usually mixtures) that burn rapidly but at a subsonic rate. Examples of this type of explosive include gunpowder, rocket propellants, and pyrotechnic mixtures (fireworks)."

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