What is one chemical used as a dry chemical extinguishing agent?

Ammonium phosphate is a commonly used dry chemical extinguishing agent because of its effectiveness in combating various types of fires, particularly those involving ordinary combustibles such as wood and paper, as well as flammable liquids. It works by coating the fuel with a layer of material that separates the fuel from the oxygen in the atmosphere, thereby interrupting the combustion process.

This compound is often utilized in portable fire extinguishers for its versatility and broad range of fire classifications, making it an essential part of firefighting strategies. In contrast, the other substances listed do not serve as effective dry chemical extinguishing agents. Ammonium nitrate, for example, is primarily used as a fertilizer and can be hazardous in other contexts. Trinitrotoluene (TNT) is an explosive, and methyl isocyanate is toxic and used mainly in agricultural practices, neither of which are appropriate or effective for extinguishing fires.