We're sorry, but OSHAcademy doesn't work properly without JavaScript enabled. Please turn on JavaScript or install a browser that supports Javascript.

662 HAZWOPER for General Site Workers III
Skip to main content

Types of Hazards

Flammables and Combustibles

  • Flammables are any solid, liquid, vapor, or gas that will ignite easily and burn rapidly. Solid flammables include dusts and powders such as charcoal and aluminum, and include low ignition point materials such as films and fibers. Flammable gases ignite easily and may be explosive if confined in a canister or cylinder.
  • DOT defines flammable liquid as:
    • a liquid having a flash point of not more than 60.5°C (141°F), or
    • a material in a liquid phase with a flash point at or above 37.8°C (100°F) intentionally heated and transported at or above its flash point (See 49 CFR 173.120 for exceptions).
  • EPA states a material exhibits the characteristics of ignitability if it is a liquid with a flash point less than 60°C (140°F).
  • Combustibles ignite only after being heated to their flashpoint temperature. Any solid that is capable of burning is considered a combustible.
  • DOT defines a combustible liquid as any liquid that does not meet the definition of any other hazard class and has a flash point above 60.5°C (141°F). A flammable liquid with a flash point at or above 38°C (100°F) may be reclassified as a combustible.

Knowledge Check Choose the best answer for the question.

2-7. Solids, liquids, vapors, or gases that will ignite easily and burn rapidly are called _____.