Metals in Wildfire Suppressants

29 April 2025 | ZeroGeoengineering.com | More scrutiny is needed regarding the widespread use of chemical fire retardants. Due to their toxicity, there is a ban on releasing these agents on waterways and endangered species habitats. PHOS-CHEK, the primary aerial retardant used in western wildfires, was developed in the early 1960s by Monsanto.

In California an independent investigation was conducted by reporters and USC researchers that analyzed samples of fire retardant collected after the Palisades, Eaton, and Franklin fires.

“Those tests found toxic heavy metals including lead, arsenic, cadmium and chromium, which can accumulate in the environment and pose risks to humans and wildlife, according to federal and state environmental agencies.”

Source

Arsenic (As) https://pubchem.ncbi.nlm.nih.gov/compound/5359596 Acute Toxic, Environmental Hazard

Cadmium (Cd) https://pubchem.ncbi.nlm.nih.gov/compound/23973 Flammable, Acute Toxic, Health Hazard, Environmental Hazard

Copper (Cu) https://pubchem.ncbi.nlm.nih.gov/compound/23978 Environmental Hazard

Manganese (Mn) https://pubchem.ncbi.nlm.nih.gov/compound/Manganese Flammable, Irritant, Environmental Hazard

Nickel (Ci) https://pubchem.ncbi.nlm.nih.gov/compound/935 Irritant, Health Hazard

Lead (Pb) https://pubchem.ncbi.nlm.nih.gov/compound/5352425 Health Hazard, Environmental Hazard

Antimony (Sb) https://pubchem.ncbi.nlm.nih.gov/compound/5354495 Acute Toxic, Irritant, Health Hazard, Environmental Hazard

Thallium (Tl) https://pubchem.ncbi.nlm.nih.gov/compound/5359464 Acute Toxic, Health Hazard

Vanadium (V) https://pubchem.ncbi.nlm.nih.gov/compound/23990#section=Hazard-Classes-and-Categories “Highly toxic, may be fatal if inhaled, ingested or absorbed through skin.”

Zinc (Zn) https://pubchem.ncbi.nlm.nih.gov/compound/23994 Flammable, Environmental Hazard

Metals in Wildfire Suppressants Marella H. Schammel, Samantha J. Gold, and Daniel L. McCurry Environmental Science & Technology Letters 2024 11 (11), 1247-1253 DOI: 10.1021/acs.estlett.4c00727

In this study, metal concentrations in several fire suppression products (some approved by the U.S. Forest Service, and some marketed for consumer use) were quantified to evaluate whether these products could contribute to increased metal concentrations observed in the environment postfire. Long-term fire retardants contained concentrations of toxic metals (V, Cr, Mn, Cu, As, Cd, Sb, Ba, Tl, and Pb) 4–2,880 times greater than drinking water regulatory limits, and potentially greater than some aquatic toxicity thresholds when released into the environment.