ABC dry chemical is not appropriate for chlorine or oxidant fires.[7]​ The resulting chemical reaction can cause an explosion or decomposition of the chemicals releasing toxic gases. In that case, water should be used.[8][9]​.

ABC dry chemical is inappropriate for certain metal fires (Class-D) and does not possess a saponification characteristic and therefore should not be used on Class K fires. ABC dry chemical has been found to be effective in initially stopping the combustion of oils or greases, however, reapplication of an additional dry chemical may be necessary due to the possibility of reheating the oils or greases to near or at their flash point. A Class K extinguisher is most effective at controlling fires that primarily involve vegetable oils, as it causes a chemical change in the oils or fats, making a flare-up much less likely. When a Class K extinguisher is not available, an ABC dry chemical extinguisher can be carefully used to control a fire involving cooking oils or fats if the operator is aware of the possible need to reapply more chemicals if the oils or fats re-ignite. (Class K).[1]​.

Due to the corrosive properties of ABC dry chemical, it is not recommended for use near aircraft or sensitive equipment.

ABC dry chemical is not appropriate for chlorine or oxidant fires.[7]​ The resulting chemical reaction can cause an explosion or decomposition of the chemicals releasing toxic gases. In that case, water should be used.[8][9]​.

ABC dry chemical is inappropriate for certain metal fires (Class-D) and does not possess a saponification characteristic and therefore should not be used on Class K fires. ABC dry chemical has been found to be effective in initially stopping the combustion of oils or greases, however, reapplication of an additional dry chemical may be necessary due to the possibility of reheating the oils or greases to near or at their flash point. A Class K extinguisher is most effective at controlling fires that primarily involve vegetable oils, as it causes a chemical change in the oils or fats, making a flare-up much less likely. When a Class K extinguisher is not available, an ABC dry chemical extinguisher can be carefully used to control a fire involving cooking oils or fats if the operator is aware of the possible need to reapply more chemicals if the oils or fats re-ignite. (Class K).[1]​.

Due to the corrosive properties of ABC dry chemical, it is not recommended for use near aircraft or sensitive equipment.