A wildfire spreading into the built environment, whether being in the Wildland Urban Interface, (WUI) or suburban neighborhoods, as we are seeing today in Southern California, is deeply devastating in more ways than just a structure being reduced to ash and a family’s loss of their home and all their belongings. We are all shocked by the large scale, intensity and rate of speed these fires have consumed Southern California neighborhoods. We often discuss evacuation, home hardening, defensible space and insurance, however there are a few more issues which should be part of the discussion which may help raise prevention awareness and mitigation efforts.
During a Structure Fire -
As a structure fire burns all the contents within the structure are also consumed. Plastics, tires, metals, solar panels, batteries, paints, herbicides, and much more are burned and the toxic gases and smoke released into the atmosphere. Firefighters and residents are immediately exposed to toxins, breathing in the smoke and absorption through the skin. Toxic smoke plumes fill the air and travel unrestricted with particles contained in the smoke floating back down to the ground, into water supplies, and continuing to be breathed in by innocent victims. Exposure to these chemicals, such as; Fluoropolymers, chloride (PVC), benzene (polystyrene), bisphenol A (BPA), phthalates, 1,3-butadiene (synthetic rubber), dioxins (byproduct of PVC production), and styrene; are linked to an increased risk of various cancers, including leukemia, lymphoma, lung, bladder, and stomach cancers depending on the specific chemical involved. The site of the structure fire, even though reduced to ash, will also retain toxins released by the burned or melted materials. Off gassing of these materials can continue for weeks further exposing residents or workers visiting the site.
After a Structure Fire –
The impacts of harmful ash particles from a fire can be long-lasting, especially if washed away by rainwater, contaminating nearby waterways and soil when it runs off, potentially carrying toxic substances like heavy metals, chemicals, and hazardous materials that were present in the burned materials, posing a significant environmental threat to aquatic life and ecosystems. During formal demolition, ash and debris is considered hazardous material and may even contain asbestos, arsenic, and lead and ultimately will be transferred to specific landfills.
The California efforts to reduce greenhouse gases are severely reduced by catastrophic fires. In 2020 wildfires released about 127 million metric tons of carbon dioxide equivalent, which was almost double the amount of greenhouse gases reduced by California since 2003.
Another lingering aspect of the impacts of wildfire, especially for hillside sites, is the loss of natural erosion controls and vegetation creating the potential for land movement and mudslides. This is something that Southern California and even Santa Cruz and San Mateo Counties have experienced in wildfire-stricken areas. Some mitigations can be put in place such as jute netting, water bars and straw waddles, however erosion from winter rains can often overwhelm mitigations and pose a threat to downhill properties and roadways. These erosion mitigations can cost thousands of dollars to implement and take many years to restabilize problematic hillsides.
Local government operations, including schools, depend on funding from property taxes. When a structure is destroyed the improvement portion of an individual parcel tax assessment is drastically reduced until the structure is rebuilt and reassessed. If a significant number of property tax assessments are significantly reduced for a Town this can drastically impact the revenue for the Town government, Fire Agency and even schools.
These affirmations are meant to highlight rarely discussed issues of wildfire and structure loss and to help prioritize and maintain efforts of wildfire prevention, home hardening, defensible space and evacuation safety improvements.
FIRE SAFE SMC continues to strive to assist San Mateo County in education and mitigation within the Wildland Urban Interface. In 2024 we completed over $1,577,165.00 of grant funded fuel mitigations and in 2025 will complete $3,329.223.00 of work. We will continue to apply for grant funding to assist local Fire Agencies, Parks Departments and Public Works Departments in making our neighborhoods and evacuation routes safer and more resilient.
It’s with great sorrow that we watch the southern portion of the State burn and realize that the lives and landscape will never be the same. We have learned a great deal from the catastrophic fires in California’s recent past and now is the time to turn the lessons learned into collaborative efforts to prevent other future catastrophic events, as much as possible. I hope all will join FIRE SAFE SMC in this effort as it will take all of us working together to make a difference.
Sincerely,

Denise Enea
Executive Director
Fire Safe San Mateo County