New Research Links Wildfire Retardants to Dangerous Heavy Metal Pollution

Wildfire retardants, the hot-pink mix of water and chemicals sprayed from airplanes by the U.S Forest service to combat wildfires, are under scrutiny after a recent study found they’re a serious source of heavy metal pollution in the U.S.

The research, conducted by a team from the University of Southern California and published in Environmental Science & Technology Letters, found that between 2009 and 2021, wildfire retardant application in the U.S. released at least 380,000 kg (more than 400 tons) of at least four toxic metals into the environment. Toxic metals — like cadmium, chromium and vanadium — accumulate in ecosystems and organisms and are linked to organ damage, cancer and neurological disorders.

“The heavy metals report from [the University of Southern California] has been a catalyst. It has created internal discussions about using these retardants,” Andy Stahl, the executive director of the nonprofit watchdog group Forest Service Employees for Environmental Ethics (FSEEE), who was not involved with the study, told EHN.