Phos-Chek

Phos-Chek is a brand of long-termfire retardants, class A foams, and gels manufactured by ICL Performance Products in Ontario, California and Moreland, Idaho.

Phos-Chek fire retardants are manufactured as dry powders or as concentrated liquids and diluted with water prior to use. The retardant is applied ahead of wildfires to homes and vegetation by ground crews and aerial firefighting units, either fixed-wing or rotary-wing aircraft.

It is currently produced as several colors, including an off-white color,red iron oxide, and a fugitive mixture that is colored red when dispersed but gradually fades to an earth-tone when exposed to sunlight. The red color aids aircrews in targeting drops of retardant.

Some of the main components of Phos-Chek retardants include ammonium polyphosphate, diammonium phosphate, diammonium sulfate, monoammonium phosphate, attapulgus clay, guar gum (or a derivative of guar gum), and trade secret performance additives. Fire retardants are manufactured as several different formulations with varying proportions of the above components.

The phosphate and sulfate salts act as fire retardants and prevent combustion of cellulosic materials. They also act as a fertilizer once the fire danger has passed. Guar gum and clay are thickening agents to prevent dispersal of the retardant after it is dropped from the plane. Other ingredients include corrosion inhibitors and flow conditioners.

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