Halogenated Hydrocarbon extinguishers have which of the following properties?

• A. Prevents re-flash after extinguishing
• B. Causes cooling of flames
• C. Increases oxygen in room
• D. Leaves a residue that fuels re-ignition

Answer: (A)

Halogenated hydrocarbon extinguishers extinguish fires primarily by chemical quenching—they interfere with the flame's chemical reactions rather than by simply cooling or displacing air. When released into the flame, the halogenated agent decomposes and releases halogen radicals that scavenge the reactive hydrogen and oxygen radicals needed for flame propagation. With these radicals neutralized, the chain reactions that keep the flame going are interrupted, so the fire cannot re-flash once the agent is dispersed.

This is different from cooling the flame (which cooling-based extinguishing methods, like water, rely on), or increasing the oxygen level (which would make burning easier, not harder). While residues from halogenated extinguishers can have other effects, they do not fuel re-ignition; the chemical inhibition of flame reactions is what prevents re-flash after extinguishing.