C-130E Hercules equipped with a Modular Airborne FireFighting System makes a Phos-Chek fire retardant drop in Southern California in October 2003.

Phos-Chek is a brand of long-term[1] fire retardants, class A foams, and gels manufactured by Perimeter Solutions in Ontario, California[2] and Moreland, Idaho.[3]


Fire retardantsEdit

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 Oct. 28 (2003)

Phos-Chek fire retardants are manufactured as dry powders or as concentrated liquids and diluted with water prior to use.[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.[7]

A Phos-Chek tank trailer at Ramona Airport

It is currently produced as several colors,[8] including an off-white color,[9] red iron oxide,[10] and a fugitive mixture that is colored red when dispersed but gradually fades to an earth-tone when exposed to sunlight.[10] The red color aids aircrews in targeting drops of retardant.[11]

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.[11][12] Fire retardants are manufactured as several different formulations with varying proportions of the above components.[13]

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.[14]

Class A foamEdit

Phos-Chek WD-881 is a mixture of anionic surfactants, foam stabilizers, and solvents including hexylene glycol. As a fire-fighting foam, it is used as a short-term fire suppressant.[15]


The first Phos-Chek retardant product was available in 1962. The Phos-Chek brand belonged to the Monsanto Company until 1998, when ownership was transferred to Solutia Inc. In 2000, Astaris LLC acquired the Phos-Chek name. In November 2005, Astaris LLC was acquired by Israel Chemicals Ltd. (ICL),[16] and the Phos-Chek brand was renamed "Phos-Chek Fire Safety Group" and assigned to the Performance Products division of ICL (ICL PPLP).[17]


The Airbase Service Center, located in Post Falls, Idaho is the headquarters for all of North America. This 30,000 square foot facility supports all bulk bases (equipment and product support to agency operated bases), SEAT bases (equipment and product support for Single Engine Air Tanker Bases), and Portable Base Operations (mobile rotor and fixed-wing bases). Various equipment maintenance and base rebuilds are performed from this location. Fabrication of liquid concentrate tanks, batch mixers, Hopper Units, and various other equipment is performed from this location.[18]


  1. ^ "USDA Forest Service - Long-term retardant specifications". Retrieved 2008-11-20.
  2. ^ "". Retrieved 2008-11-20.
  3. ^ "Phos-Chek US Airbase Service Update. 1(11), 3" (PDF). November 1, 2008. Archived from the original (PDF) on July 15, 2011. Retrieved 2008-11-20.
  4. ^ "Phos-Chek Retardant Products". Archived from the original on 2011-07-15. Retrieved 2008-11-20.
  5. ^ "Concierge-level fire protection". Los Angeles Times.
  6. ^ "Pricey Fire Protection, KTLA News". November 14, 2008. Retrieved 2008-11-20.[dead link]
  7. ^ "USDA Forest Service Aviation Management Tech Tips". Retrieved 2008-11-18.
  8. ^ US 6676858, Vandersall, Howard L. & Gary H. Kegeler, "Colorant liquid, method of use, and wildfire retardant liquids containing the same", issued January 13, 2004 
  9. ^ "". Archived from the original on August 20, 2008. Retrieved 2008-11-20.
  10. ^ a b "Phos-Chek D75 Fire Retardants" (PDF). Archived from the original (PDF) on 2011-07-15. Retrieved 2008-11-20.
  11. ^ a b "ICL Performance Products, LP. Retardant Information Sheet" (PDF). June 2008. Archived from the original (PDF) on 2009-01-06. Retrieved 2008-11-20.
  12. ^ "AIG FAQ about Phos-Chek" (PDF). Archived from the original (PDF) on 2008-09-08. Retrieved 2008-11-18.
  13. ^ "USDA Forest Service - Wildland Fire Product Information". Retrieved 2008-11-20.
  14. ^ "Phos-Chek Retardant". Archived from the original on 2008-11-20. Retrieved 2008-11-20.
  15. ^ "Ecological Effects of Fire Retardant Chemicals and Fire Suppressant Foams: Description of Chemicals - Phos-Chek WD-881". US Geological Survey. Archived from the original on 18 August 2007. Retrieved 31 March 2010.
  16. ^ "Astaris". Retrieved 5 March 2010.
  17. ^ "About Us: Phos-Chek Fire Safety Group". Archived from the original on 20 November 2008. Retrieved 5 March 2010.
  18. ^ "Welcome to Phos-Chek fire retardant, Class A foam, and gel for fire fighting". Phoschek. Retrieved 2012-02-29.

External linksEdit