Jakarta – Amid reports of wildfires raging in Los Angeles and much of Southern California, United States, firefighting teams are seen dispersing pink powder from airplanes and helicopters.
Driven by the strong Santa Ana winds, the fires have claimed at least 25 lives and scorched around 40,000 hectares in Los Angeles County. Over a week after the fires broke out, the largest blaze in the area, the Palisades Fire, is 19% contained. Los Angeles has declared a public health emergency due to the smoke.
Pink Fire Retardant
The pink powder being dropped over wildfires is known as Phos-Chek. It can be delivered aerially or applied on the ground using trucks.
This substance primarily consists of water, ammonium phosphate (commonly found in fertilizers), and pink dye. It is thickened with gum to enhance accuracy when dropped from the air.
“Phos-Chek is a fertilizer-based fire retardant. Its ingredients are the same as those used in lawn care fertilizers,” said Shannon Horn, chief operating officer at Perimeter Solutions, the manufacturer of Phos-Chek, as quoted by NBC News.
When used as a fire retardant, ammonium phosphate alters how the cellulose in plants reacts to heat. Normally, plants exposed to fire heat begin to decompose and become fuel. However, Phos-Chek acts as a coating, creating a barrier that absorbs heat energy.
This reaction produces non-flammable carbon material, slowing the spread of flames and buying firefighters valuable time.

Photo: REUTERS/Shannon Stapleton/File Photo
Photo: REUTERS/Shannon Stapleton
The primary purpose of spreading this pink powder is to help firefighters and pilots accurately create and identify fire retardant lines.
“Essentially, the dye allows pilots to see where the lines have been dropped. Without it, they wouldn’t know where the retardant lines are,” explained Horn.
Phos-Chek fades over time with sunlight exposure and washes away with water, leaving no permanent marks on the landscape.
Neptune Aviation, a Montana-based aerial tanker company, is one of the services currently delivering fire retardants to affected areas. The company operates under contracts with the US Forest Service and the California Department of Forestry and Fire Protection (Cal Fire).
Nic Lynn, vice president of operations at Neptune Aviation, said three of the company’s air tankers are deployed in Southern California. These aircraft utilize pre-established air tanker bases set up by the government.
“We go to pre-established tanker bases where they mix the retardant and pump it into the planes. Think of us like garbage trucks; we transport the product from point A to point B,” Lynn explained.
Neptune Aviation has carried out at least 93 missions and delivered over 280,000 gallons of fire retardant to combat the wildfires.
To protect ecosystems, the Forest Service and the Department of the Interior mandate that aircraft avoid dropping fire retardants within 90 meters of watercourses. Ground deliveries must also steer clear of waterways.
“However, some exceptions can be made, including when the potential damage to natural resources outweighs the possible loss of aquatic life,” the Forest Service stated.