Northern California Wildfires Leave Asbestos Behind

Illustration of potential asbestos exposure in a building

Ash from fires in Northern California may contain asbestos fibers and other toxic substances. Although the fires have been contained by firefighters, dangers now and into the future will continue to persist.

According to Sonoma County Director of Environmental Health Christine Sosko, “There can be chemicals and asbestos and lead, plus plastic particles and other dangerous substances loose at the sites of burned homes.”

This is because many of the homes probably contained asbestos products. Historically, insulation, roof materials, drywall, ceiling tiles, flooring, and asphalt are all materials commonly known to contain the hazardous substance.

When these products are ignited with fire, the smoke made of carbon dioxide, water vapor, carbon monoxide, fine particulate matter, hydrocarbons, and other organic and non-organic substances can include the minute asbestos fibers.

In Santa Rosa, California’s Office of Emergency Services (COES) will haul away materials from burned homes, however, some families are handling the matter on their own for insurance purposes.

For those individuals, the California Air Resource Board says to cover bare skin, wear a mask, and try not to get ash in the air by sweeping gently, mopping often, and not using machinery such as vacuum cleaners or leaf blowers.

According to the board, “If ash is wet, use as little water as possible.” Montana State University’s Department of Earth Sciences stated, “Over 90% of emissions from fires are small enough to enter the respiratory system and particles in the air are able to travel deep into the respiratory tract.”

“For how many structures that were burned in fairly small areas in these fires, I think that’s a first-of-its-kind event,” said Associate Director of Environmental Health for the U.S. Geological Survey Geoffrey Plumlee.

“Depending on how combusted the ash is, it’ll have different chemical compositions. And that’ll mean the ash will mix either better or worse with underlying soil,” said Plumlee.

The ash could run into nearby waterways carrying asbestos with it. Other fire remains might turn into fields of limestone or huge algae blooms that strip oxygen from rivers. It is also a serious danger to firefighters fighting the blazes, who have a higher risk of developing cancer than people in most other occupations.

According to Plumlee, “Water won’t stick to more hydrophobic ash, so rainfall might run off faster, carrying away the surrounding soil as sediment. More hydrophilic ash might mix into the water and wash into nearby streams.”

The Federal Emergency Management Agency, Environmental Protection Agency, COES, and numerous other government agencies are working to cleanup from the fires. They expect it to be the largest fire recovery drive in the state’s history.