Phos-Chek

Phos-Chek is a brand of long-term[1] fire retardants, class A foams, and gels manufactured by Perimeter Solutions, headquartered in Clayton, Missouri, United States.

[4] The retardant is applied ahead of wildfires to homes[5][6] and vegetation by ground crews and aerial firefighting units, either fixed-wing or rotary-wing aircraft.

[12] Concerns have been raised that Phos-Chek harms fish and aquatic life; and that it causes long-term effects on soils, insects, and microbiology.

[15] Phos-Chek and other retardants based on ammonium phosphate may cause algae blooms in bodies of water when washed downstream and may increase the growth of invasive plant species.

Fabrication of liquid concentrate tanks, batch mixers, Hopper Units, and various other equipment is performed from this location.

C-130E Hercules equipped with a Modular Airborne FireFighting System makes a Phos-Chek fire retardant drop in Southern California in October 2003.
A Modular Airborne FireFighting System equipped C-130E Hercules from the 146th Airlift Wing is reloaded with Phos-Chek fire retardant to be dropped on the Simi Fire in Southern California on October 28, 2003.
A Phos-Chek tank trailer at Ramona Airport
Phos-Chek prior to being mixed with water