Wildfires and Asbestos Exposure

When a wildfire reaches a neighborhood, it burns more than trees. Homes, garages, schools and businesses built before the 1980s often contain asbestos in their siding, roofing, floor tile, ceiling texture, pipe insulation and wallboard. Fire breaks those materials apart, and asbestos can end up in the ash and debris left behind. After the 2023 Maui fires and the 2025 Los Angeles fires, officials warned residents that the ash could contain asbestos along with heavy metals and other toxic substances.

The risk comes after the flames. The greatest asbestos risk comes during cleanup and rebuilding, when people sift through ash, sweep, haul debris or tear down damaged walls, and when wind and traffic stir the ash back into the air. Knowing that, you can avoid most of it.

If you or a family member has been diagnosed with mesothelioma or asbestosis, or with lung cancer after working around asbestos, the cause is usually asbestos exposure decades earlier: at work, in the military, or from a family member's work clothes. We help families trace that exposure and recover compensation.

Where the asbestos comes from

Asbestos was used for most of the twentieth century, partly because it does not burn. The same products that were sold as fireproof are what end up in the ash when an older building is destroyed:

• Siding and roofing. Asbestos-cement shingles, siding and roofing panels were common on houses and outbuildings. They do not burn, but heat cracks and shatters them. See Asbestos in cement shingles and Transite and our post on LA wildfires and asbestos roofing.
• Floors and ceilings. Vinyl-asbestos floor tile and its black mastic, and sprayed popcorn ceiling texture. See Asbestos in floor tile and Asbestos in joint compound and ceiling texture.
• Heating systems. Furnace and boiler insulation, pipe wrap, and asbestos paper wrap and tape on heating ducts in older homes. See Asbestos pipe and boiler insulation.
• Walls and attics. Joint compound, plaster and vermiculite attic insulation, much of which came from the asbestos-contaminated mine at Libby, Montana. See Libby vermiculite.

Fire is not a reliable way to destroy asbestos. Chrysotile, the most common type, does break down into a non-fibrous mineral called forsterite when heated to roughly 800°C (about 1,500°F), but a house fire does not heat every material evenly or for long enough. Cement siding, floor tile and pipe insulation are often left cracked and crumbled rather than consumed, and that broken material is more likely to release fibers than it was when intact.

Protecting yourself during cleanup

Public health agencies give the same core advice after every major fire:

• Wait for the all-clear. Do not go back into a burn area until officials allow it, and check whether your property is part of a government debris removal program before you start.
• Wear protection. A well-fitted NIOSH-approved N95 or P100 respirator (a cloth or paper dust mask is not enough), plus gloves, long sleeves, long pants, shoes and socks. People handling debris that may contain asbestos should use a P100 respirator; an N95 is not enough for asbestos.
• Keep the ash wet and still. Mist ash lightly with water before working with it. Do not use a leaf blower, and do not dry-sweep. A household vacuum spreads fine particles; use a vacuum with a HEPA filter if you must vacuum.
• Keep children and pets away. Children should not be in the area during cleanup at all.
• Don't take it home with you. Change out of work clothes before getting into your car or going indoors, wash them separately, and bag disposable gear. This is how asbestos dust reached families for generations; see take-home exposure.
• Do not haul burned building debris to an ordinary dump yourself. It may contain asbestos or other hazardous waste, and local rules govern where it can go. Small amounts of ash swept from surfaces can be bagged, but if you suspect asbestos, call your local hazardous waste agency.

Our posts covered the Maui and Los Angeles fires as they happened: Asbestos in Maui's wildfire ash, Echoes of Maui in the Los Angeles wildfires, Los Angeles wildfires air quality warning and Why some LA neighborhoods face higher toxic exposure after wildfires.

Debris removal and rebuilding

After large, federally declared wildfires, cleanup has usually come in two phases. First, EPA or state crews remove household hazardous waste, such as batteries, propane tanks, paint and pesticides, from each burned property; they may also identify and remove obvious asbestos material. Second, the Army Corps of Engineers or state contractors remove the remaining structural debris and ash, with asbestos surveys and air monitoring as part of the work. Programs differ from fire to fire, so follow the instructions of the agencies running the cleanup where you live.

If you opt out of a government program and hire your own contractor, you will usually have to show that the debris was removed and disposed of to the same standard, including an asbestos survey.

Before rebuilding or repairing a damaged building that is still standing, have it inspected for asbestos before any demolition or repair, and hire licensed abatement contractors to remove what is found. See Testing your home for asbestos.

Firefighters and cleanup workers

Firefighters, debris crews and demolition workers face far more of this dust than residents, fire after fire. Firefighting has long exposed crews to asbestos in burning and collapsing buildings, and mesothelioma is more common among firefighters than in the general population. Workers who clear burned neighborhoods day after day need full respiratory protection and decontamination, not just a dust mask.

If you have been diagnosed

Mesothelioma usually appears 20 to 50 years after exposure, and asbestosis and asbestos-related lung cancer usually 15 years or more after. If you or a loved one has been diagnosed, the most likely source is exposure long ago, at a job, in the military, or in the home, and not a recent fire. That history is what we investigate: where you worked, what products were there, and which companies made them. Many of those companies now pay claims through asbestos bankruptcy trusts.