Water- and Air-Reactive Materials

Phosphorus is a material that spontaneously combusts when exposed to air. Thus, it is shipped under water to keep it from contacting air. Fires involving phosphorns should be fought using large qnantities of water, as it will not react with the water. Care shonld be taken to ensnre these types of materials are not stored in breakable containers. Alkali metals, snch as lithinm, sodium, and potassinm, are considered water-reactive, and explosive reactions can occur when these metals contact water, releasing flammable hydrogen gas. 

Chemicals not stored in proper hazard groups can be a hazard during a fire or accident. 

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Chemical processing and mixing under controlled circumstances safely creates many of the useful products we have come to depend on in our daily lives. However, when certain chemicals come in contact with each other during uncontrolled situations, such as accidents and spills, dangerous reactions can occur. This chapter will focus on incompatible chemicals, safe storage practices, water- and air-reactive materials, and some of the hazards to responders that may occur as a result of an uncontrolled chemical reaction. 

Reactivity. Chemicals that react violently with air or water are considered hazardous examples are sodium metal, potassium metal, and phosphorus. Reactive materials also include strong oxidizers such as perchloric acid, and chemicals capable of detonation when subjected to an initiating source, such as solid, dry < 10% H2O picric acid, benzoyl peroxide, or sodium borohydride. Solutions of certain cyanide or sulfides that could generate toxic gases are also classified as reactive. The potential for finding such chemicals in a refinery is... 

Chemicals that are water or air reactive pose a significant fire hazard because they may generate large amounts of heat. These materials may be pyrophoric, that is, they ignite spontaneously on exposure to air. They may also react violently with water and certain other chemicals. Water-reactive chemicals include anhydrides, carbides, hydrides, and alkali metals (e.g., lithium, sodium, potassium). 

Chemical Reactivity - Reactivity with Water No reaction Reactivity with Common Materials Data not available Stability During Transport Stable Neutralizing Agents for Acids and Caustics Not pertinent Polymerization May occur at temperature above 50°C (120° F) Inhibitor of Polymerization Oxygen (air) plus 50 ppm of copper as copper sulfate. 

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