Note: This article was updated to include a response from Perimeter Solutions
A recent study conducted by the University of Southern California highlights the presence of heavy metals in fire retardants used in wildfire management, as reported by LA IST.
The study identifies heavy metals, including chromium, cadmium, and vanadium, in widely used fire retardants such as Phos-Chek LC-95, which is approved by the U.S. Forest Service.
The findings prompt questions about the environmental effects of these metals, particularly after wildfires.
Post-fire rains can lead to runoff, potentially spreading residual chemicals into waterways and ecosystems.
The USC study proposes that fire retardants may unexpectedly contribute to the distribution of heavy metals in the environment following wildfires.
Analysis of runoff after the 2009 Station Fire revealed elevated cadmium levels, leading researchers to explore fire retardants as a possible source, alongside natural sources such as burned vegetation and soil.
Dr. Daniel McCurry, an associate professor at USC and co-author of the study, stated: “Unfortunately, Phos-Chek LC-95 … contained potentially concerning concentrations of a few heavy metals, including chromium, cadmium, and vanadium.
“It’s not quite a smoking gun, but it at least suggests that it’s quite possible these fire suppressants contribute to metal release observed after fires.”
According to experts, heavy metals in waterways can impact food chains, posing potential risks to organisms as the metals move from algae to fish, potentially affecting endocrine systems.
Dr. Lauren Magliozzi, a researcher from the University of Colorado, Boulder, who studies metal contamination but was not involved in the USC study, said: “This is a really important contribution to the literature. To start thinking about different sources of metal contamination after fires.”
Magliozzi added that acute metal toxicity in ecosystems could lead to ecosystem breakdown, creating risks for ecological collapse.
Federal and state agencies, such as the U.S. Forest Service and Cal Fire, recognize the environmental risks posed by phosphates in fire retardants, regulating retardant use near waterways.
However, Cal Fire pointed out that Phos-Chek LC-95, tested in the study, differs from its own fire retardant variant, which Perimeter Solutions did not provide for comparison.
The USC research team clarified that while their findings raise concerns, they do not yet confirm a direct link between fire retardants and heavy metal spread post-wildfire.
Dr. McCurry noted: “We don’t quite have a direct A to B connection between metals in the fire suppressants and metals released by wildfires.”
To understand the extent of heavy metal contamination from fire retardants, the USC team suggests further research, particularly in measuring heavy metal levels in waterways before and after wildfires.
This research could help determine if fire retardants are a significant contributor to post-fire contamination, especially in areas affected by heavy rain.
Such data would provide clarity on whether fire retardants should be modified or regulated further to protect ecosystems.
In response to the report, Perimeter Solutions said: “Researchers from the University of Southern California (USC) released a report on the use of PHOS-CHEK® fire retardant.
“PHOS-CHEK is an advanced fire safety solution that has been used by the US Forest Service, CAL FIRE, and other fire management organizations for more than 60 years, playing a critical role in protecting property and saving countless lives from the devastation of wildfires.
“The PHOS-CHEK product that was tested for the USC study, PHOS-CHEK® LC95W, has never been used in aerial applications.
“All PHOS-CHEK fire retardants used in aerial firefighting must be fully qualified by the USDA Forest Service.
“All fully qualified fire retardants must pass extensive testing to confirm they meet strict standards for aquatic and mammalian safety.
“The USDA Forest Service also issued a comprehensive 562-page Environmental Impact Statement on the use of PHOS-CHEK fire retardant, following years of research, concluding that it was safe for use in aerial firefighting.
“The active ingredient in all PHOS-CHEK fire retardants is the same material used in agriculture to produce food.
“The amount used for retardant is less than 0.01% of what’s used in agricultural and other applications.”
The University of Southern California’s recent study has raised concerns over the presence of heavy metals, such as chromium, cadmium, and vanadium, in commonly used fire retardants.
These findings, published in LA IST, suggest that fire retardants may unintentionally contribute to heavy metal spread in ecosystems, particularly through runoff after wildfires.
Despite current regulations limiting retardant drops near waterways, the study recommends further research to understand fire retardants’ role in post-fire contamination.
Experts acknowledge the potential ecological risks from heavy metals accumulating in food chains and affecting species at multiple trophic levels.
However, researchers caution that a direct link between fire retardants and heavy metal spread remains unconfirmed, with further data needed to clarify the environmental impact.
