Manufacturing Skill Standards Council (MSSC) Safety Assessment Practice Test

A physical hazard resulting from a substance that may spontaneously combust when exposed to air is called _____________.

1. Flammable

2. Pyrophoric

3. Compressed gas

4. Explosive

The correct answer is: Pyrophoric

A physical hazard resulting from a substance that may spontaneously combust when exposed to air is called pyrophoric. Pyrophoric materials are unique in that they ignite spontaneously upon contact with oxygen, which poses significant safety risks in manufacturing and handling practices. These substances can catch fire at temperatures as low as room temperature, making them particularly hazardous if not stored and handled correctly. Flammable substances, while capable of catching fire easily, do not necessarily ignite spontaneously in air; they require an external ignition source. Compressed gases refer to gases that are stored under pressure in a container, and while some compressed gases can also be flammable or explosive, they do not possess the same spontaneous ignition characteristics as pyrophoric materials. Explosives, on the other hand, undergo a rapid chemical reaction producing gas and heat but are distinct from pyrophoric substances in their behavior and interactions with the environment. Understanding the specific characteristics of these materials is crucial for safety in manufacturing settings.