What are the pink powder fire crews going down in LA, and how do they work?
Some of the sights coming out of Los Angeles County over the past week are what we’ve come to expect from wildfires: dramatic flames, orange skies and damaged buildings.
But what about the pink powder covering the neighborhoods?
The reflective material that covers the roads, cars and places is actually fireproof, brought down by the red or pink colored aerial fire extinguishers.
Unlike water droplets, which target active flames, fire retardant is dropped by aircraft ahead of the fire path to slow the fire’s progress and allow crews to build fire lines.
Thousands of gallons of fire retardant have been dumped in Los Angeles County since the fires broke out last week, officials said. The deadly fires have killed at least 25 people, destroyed more than 12,000 buildings and displaced tens of thousands of civilians so far.
What exactly is a fire retardant?
Fire retardants are made from chemical fertilizers such as ammonium phosphates. They often include luminous pigments to assist pilots in accurately dropping the retardant.
They work to slow the fire by cooling and covering the plants that act as fuel for the fire, depriving the fire of oxygen, and slowing the burning process “as the inorganic salts of the retardant alter the combustion process,” according to the US Forest Service.
Phos-Chek, made by the company Perimeter Solutions, is a retardant used in Los Angeles County, and is widely used in Canada. It is also the most used fire extinguisher in the world, according to a 2022 report from the Associated Press.
Although there are several formulations, it usually comes in a powder concentrate that is mixed with water before being dropped into the tanks.
Is it safe?
In general, approved fire extinguishers are not considered toxic to humans – although direct inhalation, eye contact or use can cause irritation, and scientists say more research on long-term exposure is needed.
But fire retardants can be toxic to fish or other aquatic life if they get into the water. For this reason, the US Forest Service prohibits the disposal of fire retardants within 300 feet of waterways or specially designed evacuation areas, “unless human life or public safety is threatened.”
A study published last year in the journal Environmental Science & Technology Letters found that some fire extinguishers, including Phos-Chek LC-95W, contain toxic metals, including lead and arsenic.
Representative with the US Forest Service he told NPR that the LC-95 is phased out in 2025 in favor of the new MVP-Fx design. According to Perimeter data, Phos-Chek MVP-Fx i less toxic fishing has the structure of the old LC-95.
Perimeter has previously said residents should try to clean malfunctioning equipment with mild soap and water as soon as safety allows.
“The longer the retardant dries, the more difficult it is to remove completely,” the company said in a nutshell. Pressure washers can be used in large areas, it added.
The bright color will fade slightly with exposure to the sun.
Wayne Coulson, CEO of Vancouver-based Coulson Aviation says most of the flights his company has made to support Los Angeles firefighters have been at night.
Wildfires are linked to a variety of health problems, with research showing long-term smoke inhalation can have a negative impact on the lungs and heart, and increase the risk of dementia more than other forms of air pollution.
The US Forest Service has been using aerial firefighting since the 1950s, according to its website, but its use has gone through many changes over the years as older structures were phased out and regulations changed.
In 2005, the US District Court for the District of Montana ruled that the Forest Service violated the National Environmental Policy Act by not conducting a proper analysis of the aerial firefighter’s impact on the environment and endangered species. After years of back and forth, the US Forest Service conducted a review and implemented a no-discharge requirement in waterways and diversion areas in a 2011 decision.
Last year, the US Forest Service announced it had decided to enter into an agreement with Compass Minerals for magnesium chloride-based aerial fire extinguishers after tests found corrosion in the aerial tanks used to plant the defunct company.
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