Long-term flame retardants (LTFRs) are a critical tool for slowing the spread of wildfires, but the chemicals currently used—primarily ammonium phosphate—can wash into nearby waterways, contributing to eutrophication and harming aquatic ecosystems. Additional formulation components, including synthetic dyes and trace metals, raise further environmental and occupational health concerns. This project challenged the team to explore safer formulations that maintain firefighting performance while reducing ecological impacts.
Using a green chemistry framework, the team worked with CalFire to evaluate the technical performance and hazard profiles of both existing ingredients and potential alternatives. The analysis focused on three key functions of current formulations: char formation to slow combustion, visible dyes for aerial deployment, and additives that ensure effective dispersion from aircraft.
The report identifies several promising plant-derived and low-hazard alternatives. Phytic acid, lignin, and pomegranate rind extracts show strong potential as char-forming agents, often matching or exceeding the char-formation performance of ammonium phosphate while reducing aquatic toxicity. For aerial visibility, beetroot powder and pomegranate anthocyanins offer biodegradable alternatives to synthetic dyes. The team also explored silica particles as a carrier material to improve dispersion and reduce the amount of active chemicals required.
Together, these findings demonstrate that bio-based chemistry and thoughtful reformulation strategies could significantly reduce the environmental footprint of wildfire retardants while preserving their effectiveness as a critical firefighting tool.