Understanding the Role of Pink Flame Retardants in Combating California Wildfires

Aircraft are deploying more than just water to combat the fires raging through Los Angeles. They are releasing hundreds of thousands of gallons of hot-pink fire suppressant in an urgent attempt to halt the flames before they destroy more neighbourhoods. Since last Tuesday, these fires have claimed at least 24 lives, displaced thousands, and destroyed over 12,000 structures.

The fires have scorched approximately 160 square kilometres, driven by strong Santa Ana winds, according to Cal Fire. Fire agencies consider suppressants crucial in fighting forest fires. However, questions arise about their composition and safety. The fires are rapidly spreading through canyons and rugged areas, making it challenging for ground firefighters to reach them.

Fire Suppressants in Use

Cal Fire explains that while fire suppressants are effective, they have limitations. Strong winds can make flying at low altitudes dangerous and may disperse the retardant before it reaches the ground. Various agencies, including Cal Fire, the US Forest Service, and local fire departments, have been deploying both fire retardant and water.

Aerial fire suppressants typically consist of water, ammonium phosphate (a type of fertiliser), and iron oxide for visibility, according to Daniel McCurry from the University of Southern California. The Forest Service has used 13 aircraft to deliver suppressants on the Los Angeles fires. These substances help starve a fire of oxygen and slow its spread by cooling and coating vegetation.

Environmental Concerns

While generally safe for humans, there are concerns about the environmental impact of fire suppressants. The Forest Service prohibits their use over waterways and endangered species habitats unless human life is at risk due to potential harm to fish and wildlife. McCurry's research found heavy metals like chromium and cadmium in some suppressants used by the US Forest Service.

McCurry suggests that these suppressants might contribute to increased levels of heavy metals in waterways downstream from wildfires. However, proving the source of these metals remains challenging. Perimeter, which supplies fire retardant to the Forest Service, states that McCurry's research involved a formulation not used in California and no longer employed by the Forest Service.

Health Implications

The use of fire retardants is crucial for extinguishing wildfires that pose health risks due to toxic particles that can cause respiratory and heart issues. Studies indicate that wildfire smoke has contributed significantly to air pollution in the western US as rising temperatures fuel more destructive fires. Research also suggests that wildfire smoke may be more harmful to brain health than other air pollutants.

Edward Goldberg from Perimeter emphasises that wildland fire retardant is essential for saving lives, protecting communities, and containing fires. McCurry acknowledges the need for further research on fire suppressants but recognises their importance. "If there was a brush fire coming for my house," he said, "I'd still rather paint a lot of fire retardant in front of it."