Phos-Chek is a brand of long-term

fire retardant A fire retardant is a substance that is used to slow down or stop the spread of fire or reduce its intensity. This is commonly accomplished by chemical reactions that reduce the flammability of fuels or delay their combustion. Fire retardants ...

s, class A foams, and

gels A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady state, although the liquid phase may still ...

manufactured by Perimeter Solutions, headquartered in

Clayton, Missouri Clayton is a city in and the county seat of St. Louis County, Missouri, and borders the independent city of St. Louis. The population was 17,355 at the 2020 census. Organized in 1877, the city was named after Ralph Clayton, a citizen who donated ...

, United States.

Products

Fire retardants

Modular Airborne Fire Fighting System being filled with a 146th Airlift Wing C-130 Hercules in the background

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

wildfire A wildfire, forest fire, or a bushfire is an unplanned and uncontrolled fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identified as a ...

s to homes and vegetation by ground crews and

aerial firefighting Aerial firefighting, also known as waterbombing, is the use of aircraft and other aerial resources to Wildfire suppression, combat wildfires. The types of aircraft used include fixed-wing aircraft and helicopters. Smokejumpers and rappellers ar ...

units, either

fixed-wing A fixed-wing aircraft is a heavier-than-air aircraft, such as an airplane, which is capable of flight using Lift (force), aerodynamic lift. Fixed-wing aircraft are distinct from rotorcraft, rotary-wing aircraft (in which a Helicopter rotor, r ...

rotary-wing A rotary-wing aircraft, rotorwing aircraft or rotorcraft is a heavier-than-air aircraft with rotor wing, rotary wings that spin around a vertical mast to generate lift (force), lift. Part 1 (Definitions and Abbreviations) of Subchapter A of Chapt ...

aircraft. As of 2022, Phos-Chek LC-95A is the most used fire retardant in the world. Phos-Chek Tank

Phos-Chek is produced in several colors, including red, uncolored, and ''

fugitive A fugitive or runaway is a person who is fleeing from custody, whether it be from jail, a government arrest, government or non-government questioning, vigilante violence, or outraged private individuals. A fugitive from justice, also known ...

.'' The colored retardant 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 phosphate (DAP; IUPAC name diammonium hydrogen phosphate; chemical formula (NH4)2(HPO4)) is one of a series of water- soluble ammonium phosphate salts that can be produced when ammonia reacts with phosphoric acid. Solid diammonium ph ...

ammonium sulfate Ammonium sulfate (American English and international scientific usage; ammonium sulphate in British English); (NH4)2SO4, is an inorganic salt with a number of commercial uses. The most common use is as a soil fertilizer. It contains 21% nitrogen a ...

ammonium dihydrogen phosphate Ammonium dihydrogen phosphate (ADP), also known as monoammonium phosphate (MAP) is a chemical compound with the chemical formula (NH4)(H2PO4). ADP is a major ingredient of agricultural fertilizers and dry chemical fire extinguishers. It also has ...

, attapulgus clay,

guar gum Guar gum, also called guaran, is a galactomannan polysaccharide extracted from guar beans that has thickening and stabilizing properties useful in food, feed, and industrial applications. The guar seeds are mechanically dehusked, hydrated, mi ...

(or a derivative of guar gum), and

trade secret A trade secret is a form of intellectual property (IP) comprising confidential information that is not generally known or readily ascertainable, derives economic value from its secrecy, and is protected by reasonable efforts to maintain its conf ...

performance additives. Fire retardants are manufactured as several different formulations with varying proportions of the above components.

Potential harms

Concerns have been raised that Phos-Chek harms fish and aquatic life; and that it causes long-term effects on soils, insects, and microbiology. A group based in Oregon called Forest Service Employees for Environmental Ethics sued the U.S. Forest Service, claiming the service violated the

Clean Water Act The Clean Water Act (CWA) is the primary federal law in the United States governing water pollution. Its objective is to restore and maintain the chemical, physical, and biological integrity of the nation's waters; recognizing the primary respo ...

by spraying Phos-Chek without assessing the product's harmful effects on waterways. In 2023, a Montana judge agreed that the USFS was violating the Clean Water Act but declined to prohibit the agency from using Phos-Chek, instead requiring the USFS to apply for a permit from the EPA but permitting USFS to continue using the product in the meantime. The

phosphate Phosphates are the naturally occurring form of the element phosphorus. In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthop ...

and

sulfate The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ...

salts act as

s and prevent

combustion Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...

of cellulosic materials. Phosphate can also act as a

fertilizer A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Man ...

once the fire danger has passed.

Guar gum Guar gum, also called guaran, is a galactomannan polysaccharide extracted from guar beans that has thickening and stabilizing properties useful in food, feed, and industrial applications. The guar seeds are mechanically dehusked, hydrated, mi ...

and

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

are

thickening agent A thickening agent or thickener is a substance which can increase the viscosity of a liquid without substantially changing its other properties. Edible thickeners are commonly used to thicken sauces, soups, and puddings without altering their ...

s to prevent dispersal of the retardant after it is dropped from the plane. Other ingredients include

corrosion inhibitor A corrosion inhibitor or anti-corrosive is a chemical compound added to a liquid or gas to decrease the corrosion rate of a metal that comes into contact with the fluid. The effectiveness of a corrosion inhibitor depends on fluid composition and ...

s and flow conditioners. Phos-Chek and other retardants based on ammonium phosphate may cause

algae bloom An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in fresh water or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompass ...

s in bodies of water when washed downstream and may increase the growth of

invasive plant An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native speci ...

species.

Class A foam

Phos-Chek WD-881 is a mixture of anionic surfactants, foam stabilizers, and solvents, including hexylene glycol. As a

fire-fighting foam Firefighting foam is a foam used for fire suppression systems, fire suppression. Its role is to cool the fire and to coat the fuel, preventing its contact with oxygen, thus achieving suppression of the combustion. Firefighting foam was invented b ...

, it is used as a short-term fire suppressant.

History

The first Phos-Chek retardant product was available in 1962 and was the first phosphate-based fire retardant approved by the United States Forest Service. The Phos-Chek brand belonged to the

Monsanto Company The Monsanto Company () was an American agrochemical and agricultural biotechnology corporation founded in 1901 and headquartered in Creve Coeur, Missouri. Monsanto's best-known product is Roundup, a glyphosate-based herbicide, developed in ...

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), and the Phos-Chek brand was renamed "Phos-Chek Fire Safety Group" and assigned to the Performance Products division of ICL (ICL PPLP). In 2018, private investment firm SK Capital acquired the Fire Safety and Oil Additives businesses of ICL and renamed it Perimeter Solutions, and the Phos-Chek brand was acquired with the business.

Manufacturing

The Airbase Service Center, located in

Post Falls, Idaho Post Falls is a city in Kootenai County, Idaho, United States. It is the gateway city to Northern Idaho off Interstate 90, just west of Coeur d'Alene, and east of Spokane, Washington. The population is an estimated 44,798 in 2023 according to ...

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.

References

External links

* * {{Clayton, Missouri Fire suppression agents Flame retardants Aerial firefighting Post Falls, Idaho Products introduced in 1964 Clayton, Missouri