Perimeter Solutions has confirmed that San Diego County will use its PHOS‑CHEK long‑term fire retardant on over 200 miles of roadways identified as high fire-risk, including the heavily trafficked Wildcat Canyon corridor.
The county maintains nearly 2,000 miles of road, and this preventive treatment forms part of its wildfire readiness strategy.
Wildcat Canyon, known for steep terrain and frequent traffic, is particularly vulnerable to fire ignition from overheated vehicles, and also functions as a key evacuation route for eastern parts of the county.
Ground-based PHOS‑CHEK works similarly to aerial applications, though in an uncoloured form designed for early-season application on flammable vegetation, maintaining its effectiveness until significant rainfall.
San Diego officials report that applying PHOS‑CHEK provides a solid barrier that significantly slows ignite-on sparks, giving firefighters vital extra time to control fire spread.
The initiative is financed in part by the Community Wildfire Defense Grant programme, created under the Bipartisan Infrastructure Law to support high-risk communities.
Previous field implementations have demonstrated the product’s effectiveness: in Wildcat Canyon, a fire projected to spread across half an acre was reduced by approximately 99% following PHOS‑CHEK treatment. In another test elsewhere in California, no fires occurred in treated areas across a full season.
San Diego County Supervisor Joel Anderson emphasised the importance of proactive measures, noting, “My constituents have consistently said that fire safety and prevention is a top priority… this innovative approach helps keep everyone in our county safer.”
Perimeter Solutions COO Shannon Horn added, “We are proud to continue our partnership with the County of San Diego… By leveraging advanced fire retardant technologies like PHOS‑CHEK, San Diego County is leading the way in wildfire prevention.”




