Absolutely not! We have two different tech tips that point out situations where you cannot use mono-ammonium phosphate (ABC dry chemical).

Tech Tip #5, talks about oxidizers. One of the more common places you may run into oxidizers would be in pool chemical supplies and waste water treatment facilities. If ABC dry chemical is used around these chemicals, a violent reaction may occur.

Tech Tip #20, talks about aircraft. Mono-ammonium phosphate is acidic in nature. It will cause corrosion on untreated metal like any other acid would if it is not cleaned up quickly after the incident or discharge. The problem with aircraft is that there are so many places for the chemical to hide making complete clean up impossible. It would be necessary (as one airline said a few years ago) to take the airframe apart “rivet by rivet” in order to clean it properly. Without complete clean up, the airframe will corrode over time and (being subject to severe stress during its use) it may fail.

In addition to these cases where ABC dry chemical cannot be used, there are other cases where you should not use it.

Cooking grease hazards should have only Class K extinguishers available in order to saponify the cooking grease and to cool the grease down safely (more on this later). ABC dry chemical will not work on these fires.

ABC dry chemical may have only a limited effect on deep seated Class A fires, or Class A fires that involve burning embers that “burrow” into the fuel (such as cotton bales, wood chip piles.)

Mono-ammonium phosphate works on Class A fires by melting into a sticky, molten residue at about 350 deg. F. This residue sticks to burning embers and excludes oxygen, interrupting the combustion process. In a deep-seated fire like a cotton bale or a wood chip pile, the dry chemical will have trouble penetrating into the material where the burning embers are “burrowing”. Water mist, water spray or foam would be the choice for combating these types of fires.

Unfortunately, the ideal fire extinguishing agent that can be used on all types of fires and in all types of situations has yet to be discovered. ABC dry chemical is certainly versatile, but it is by no means the answer to every fire hazard.