Class A fires involve common combustibles like wood, paper, cloth, rubber, trash and plastics. They are common in typical commercial and home settings, but can occur anywhere these types of materials are found.

 Class B fires involve flammable liquid gases, solvents, oil, gasoline, paint, lacquers, tars and other synthetic or oil-based products. These fires often spread rapidly and, unless properly secured, can re-flash after the flames are extinguished.

Class C fires involve energized electrical equipment; like wiring, controls, motors, processing panels or appliances. They can be caused by a spark, power surge or short circuit and typically occur in locations that are difficult to reach and hard to see.

Class D fires involve combustible metals like magnesium and sodium. These fires are unique industrial hazards which require special dry powder agents.

Class K fires involve combustible cooking media like oils and grease commonly found in commercial kitchens. These require a special wet chemical extinguishing agent that is specially suited for extinguishing and suppressing these extremely hot fires that have the ability to re-flash.