Fire retardant refers to a colored mix of chemical compounds dropped over wildfires to impede their progress. One example is PHOS-CHEK®, primarily composed of phosphates and water. It was used during the California wildfires of 2017-2018 and spared significant areas from destruction. Unfortunately, fire retardant tends to find farms—including cannabis crops.
In a single week in late 2017, California state firefighters dumped over 2 million gallons of PHOS-CHEK. Firefighters do their best to limit drops and avoid certain areas as the chemical ingredients (e.g., ammonia from ammonium phosphate) alter soil chemistry and biology. Even so, tens of thousands of gallons dumped from the sky on a windy day resists precision.
Of course, cannabis farms are not immune to wildfire. An estimated 30-40% of California’s cannabis farmers were directly affected by the 2017/2018 wildfires. Several lost their crops to fire, and smoke/ash damage was also widespread (including toxic deposits from burned man-made structures). Even so, PHOS-CHEK products are not a solution for farmers. They are considered to pose risk to small omnivores, songbirds, and fish at sufficient doses. How retardant affects human health via cannabis consumption is unclear.
Plants may adapt to limited exposure to PHOS-CHEK since the chemicals nitrogen and phosphate are fertilizers. However, the United States Department of Agriculture (USDA) notes that “uncontrolled application for other than their intended purpose is not recommended.” Ultimately, fire retardant is a form of contamination, and consumption or sale of affected cannabis must be avoided. Refinement and remediation of wildfire-tainted cannabis is though not impossible. Due to the safety risks, it should not enter the market.
Based in California, Fusion Farms unknowingly purchased biomass contaminated with retardant. They used distillation to refine their extract and oddly discovered the formation of crystal delta-10-tetrahydrocannabinol (Δ10-THC). Although they were unable to repeat the results with fire retardant, they did discover that a free radical initiator boosted Δ10-THC exponentially.
What did the fire retardant do the cannabis? What would it do to the person consuming the cannabis? Would it resist the flame of a lighter, providing key evidence as to its condition? That’s a stretch, sure. It’s fair to say that many questions remain—and that no consumer wants to consume fire retardant.
Image: Public domain; U.S. Air Force photo by Senior Master Sgt. Dennis W. Goff