- In the 21st century, petrochemical-based building materials and furnishings have replaced traditional wood, fabric and metal materials in homes worldwide. But plastics are more flammable and release persistent toxic chemicals when burned or exposed to high heat.
- Also over the last 25 years, wildfires have multiplied and intensified due to global warming, and often now jump the wildland-urban interface, burning whole neighborhoods and leaving behind a dangerous toxic home legacy.
- Homeowners whose houses survive such wildfires are often stunned to learn that their homes are a toxic health threat, unlivable and a total loss.
- The multibillion-dollar production and wide-ranging export of plastic building materials and home furnishings, and the dramatic surge in wildfires, has made this a global problem impacting communities in the U.S., China, Australia, Brazil, Canada, Portugal and beyond.
Rob Wilson stood on his home’s back deck in Flagstaff, in the U.S. state of Arizona, as the wildfire approached. All was chaos: Utility trucks rushed through his neighborhood, shutting off gas and electricity. Fire engines wailed and roared by, as police cruisers blared evacuation warnings.
But Wilson had prepared for this moment. When he purchased this idyllic property abutting Coconino National Forest in 2004, he knew his home was at risk for wildfires.
He consulted with buddies at the local fire department and in the building trades, and ran a 4-inch (10-centimeter) pipe from his timber-constructed home to the road to provide for a fire hydrant, and cleared a firebreak around the property. His siding was cement-based, his porch built from fire-resistant tropical hardwood. More importantly, he insulated the home with spray foam insulation, sealing soffit vents so no embers could get in the attic and set his house ablaze.
But this wildfire, like many that have ignited in the past decade, was an altogether different beast than what he’d planned for.
Wilson’s wife and the family mutt had left hours earlier, towing a loaded horse trailer. Now, a bulldozer booked it through the yard. The operator paused just long enough to yell, “Get out of here now! It’s right behind me!”
When Wilson drove away, he took a last look at the house, thinking he wouldn’t see it again.
The home did survive, while his neighbors’ houses burned down to their foundations. But Wilson came to wish his home had burned too. Because it’s now too toxic to live in.
Plastic homes: The global norm
Wilson’s story is becoming increasingly common as wildfires burn hotter, faster and more frequently. The World Resources Institute estimates that the area burned by forest fires increased globally by about 5.4% per year from 2001 to 2023. Nearly 6 million more hectares (15 million acres) of tree cover is now burned per year, equivalent to the area of Croatia. And not just in the U.S. West, but in Canada, the Amazon Rainforest, the U.K. and EU, and in Russia.
These fiercer fires are now more frequently jumping from the wilderness into urban areas. Almost 3,000 homes were destroyed in a massive bushfire in Australia in 2019, while more than 150 homes burned in Halifax, Canada, in May 2023. In the Valparaiso region of Chile in February, a fire destroyed more than 1,000 homes, and in the same month, wildfires tore through 25 regions of China, burning forests and cities alike.
Homes today are different, too: Across the world — from California to Chile to China and Portugal — they’re often covered and filled with synthetic materials, including polyurethane spray foam insulation, vinyl siding, laminate flooring, synthetic carpeting, PVC pipes, polyester and pressed-wood furniture, and plastic electronics.
You could say that the construction boom worldwide is now fueled not just by concrete, but by plastic. The global value of plastic building material exports rose in the decade from 2012 to 2022, from $10 billion to more than $16 billion, with China dominating their manufacture, followed by Poland and Germany. And that boom is expected to continue: In China alone, demand for plastic construction materials could soar to almost $44 billion by 2033, with that nation continuing to be a hotspot for rapid construction and urbanization — as well as for wildfires that jump into villages and cities.
The United States has a robust domestic plastics manufacturing industry, while still importing on top of that, buying more than 17% of the global value of synthetic construction materials. Other fire hotspots also import plastic construction materials, such as Australia (with imports of $274 million in 2022) and Brazil ($33 million).
These petrochemical building materials are a far cry from the traditional wood, fabric and metals used in the past. In fact, the favorite of plastic construction firms is polyvinyl chloride, or PVC, which critics say is the most toxic type of plastic on the market.
These synthetics come with a high toxic cost: Of the more than 16,000 chemicals present in plastic products, more than 4,200 are persistent, bioaccumulative, mobile and/or toxic, though hazard information remains lacking for more than 10,000.
When modern homes burn, they create a noxious toxic smoke that can include lead, arsenic, asbestos and cyanates. According to a 2022 study, burning the type of plastics found in homes produces smoke that is more toxic than wood or cardboard. It also causes more inflammation and lung injury in mice, and is more mutagenic.
This highly hazardous smoke then flows over and through nearby houses, depositing toxic soot and ash on indoor surfaces, which absorb them and become “reservoirs” of hazardous chemicals like benzene and cyanide. According to a 2023 study, the surfaces in a surviving home then slowly release hazardous compounds over time into the indoor air of the home.
Living inside a toxic chemical reservoir
After the April 2022 wildfire, when Wilson and his wife came back to the neighborhood, they were sad to see neighbors’ homes entirely gone, but relieved to find their place still standing. The fire had gotten close enough to melt a sliding screen door and break some windows. The inside was coated in soot and ash. But it was largely intact.
“We thought we were the lucky ones,” he says. So they set about cleaning the interior and contacting their insurance company about visible damages.
The first clue something was wrong arose after his and his wife’s annual physicals. Their blood tests came back with abnormally low white blood cell counts. The two also noticed the house smelled wrong. A friend recommended they hire an industrial hygienist to test the home.
Months after the fire, and after the house had been thoroughly cleaned several times, Dawn Bolstad-Johnson, a published author of peer-reviewed research on hazardous chemical exposure from fires, came with a colleague to take samples around the house. “They walked in the front door and immediately turned around and went back and got masks,” Wilson remembers. Bolstad-Johnson and her colleague spent nine hours sampling the air and taking surface dust samples.
Six days later, she called Wilson and told him he and his wife needed to move out immediately and leave everything behind. Her testing found that every material in the building was contaminated, with toxic acrolein, formaldehyde, glutaraldehyde, hydrogen chloride and nitrogen dioxide — all at levels considered dangerous for workers if exposed to them for even 15 minutes. (There are no similar enforceable U.S. standards for home indoor air quality.)
This wasn’t the first time Bolstad-Johnson had made a call like this.
She’s sampled homes that survived the catastrophic Paradise fire in California and the Marshall fire in Colorado, and says thousands of people are living today in post-wildfire homes that are weeping carcinogenic and reproductive toxic chemicals from their walls. “I’m fighting for homeowners all over the place,” she says.
Five minutes to flashover
Toxic residue isn’t the only fire danger that comes with today’s synthetic homes. Homes filled with plastic materials burn hotter and faster, making it harder for homeowners to flee.
In 2020, the Fire Safety Research Institute by UL released a video documenting an experiment in which two different living rooms — one filled with traditional natural furnishings and decor, and one filled with modern synthetic furnishings — were lit on fire.
The traditional living room’s wood and cotton-stuffed couch and cotton curtains did burn, but slowly, over 30 minutes, releasing a white smoke. But the synthetic room, with a polyurethane foam-filled sofa, engineered wood furniture, and polyester curtains, spilled out oily black smoke, and reached flashover in less than five minutes. That’s when the room gets so hot all the surfaces ignite simultaneously. It’s impossible to survive at that point.
Today, you’re more likely to die in a reported home fire than in 1980, partly due to fast-burning synthetic materials and the noxious black smoke they produce. Maryland state fire marshal Brian S. Geraci has called a modern synthetic couch a “block of gasoline.”
“People are getting trapped more and more inside their homes,” Bolstad-Johnson says. “And it’s because synthetic materials burn hotter and faster. We’re living in a very synthetic society, from the clothes we wear, to the cabinets, to the furniture, to the computers we’re talking on right now. Everything is plastic, or there’s a plastic component.”
A battle for good science
In the state of Hawai‘i, residents whose homes survived the devastating Lāhainā fire on the island of Maui last year are locked in a battle with their insurance companies. The reason: Their homes are still standing but too toxic to live in.
Smoke from the Maui fire, which burned cars, homes and electronics, carried chemicals linked to brain tumors and other cancers. But because there are no state or federal laws or industry standards that regulate how to assess and remediate toxic smoke residues in homes after a wildfire, insurance companies are paying out to homeowners many times less what independent experts say it will cost to truly make homes safe and habitable again.
While Wilson’s Arizona home is mostly timber, Bolstad-Johnson’s report noted that the polyurethane spray foam insulation inside its walls likely started breaking down when temperatures got hot enough to break windows.
That degraded foam is where Wilson believes most of the ongoing contamination is coming from. Because spray foam soaks into every surface, it’s almost impossible to tear it out completely from a home’s walls after a fire. He now believes the only safe path forward is to tear down the house he strived so hard to save and start over.
“The foam I think saved Rob’s house [from incineration],” Bolstad-Johnson says. “But his house is still totaled. It’s not only the forest that burned behind him, but all the homes around him were leveled, like incinerated, gone.”
A consultant and veteran of the U.S. Navy, Wilson was well prepared for a protracted bureaucratic battle with his insurance company. When I talked to him in January of this year, he and his wife were living in a rented trailer parked in their front yard paid for by insurance. In April, he finally reached a settlement with the insurance firm — 23 months after the fire. But he and his wife are still living in the trailer while they decide on their next move.
Today, most modern homeowners, especially those who don’t have good home insurance, who have low income, or who live in developing countries, won’t be so lucky. Meanwhile, wildfires continue growing hotter, faster and more frequent, as homes and their contents grow more synthetic and toxic.
That troublesome dichotomy raises a question for 21st-century homeowners: Is the convenience and cost savings of a plastic home worth the risk in a warming world?
Banner image: A firefighter wears a breathing mask after the Maui fire to protect himself from toxic vapors. Dawn Bolstad-Johnson, an industrial hygienist, has published on the toxic hazards of burned buildings to firefighters. Image by U.S. Army National Guard/Staff Sgt. Matthew A. Foster via Wikimedia Commons (Public domain).
Citations:
Kim, Y. H., Rager, J. E., Jaspers, I., & Gilmour, M. I. (2022). Computational approach to link chemicals in anthropogenic smoke particulate matter with toxicity. Chemical Research in Toxicology, 35(12), 2210-2213. doi:10.1021/acs.chemrestox.2c00270
Kim, Y. H., Warren, S. H., Kooter, I., Williams, W. C., George, I. J., Vance, S. A., … Gilmour, M. I. (2021). Chemistry, lung toxicity and mutagenicity of burn pit smoke-related particulate matter. Particle and Fibre Toxicology, 18(1). doi:10.1186/s12989-021-00435-w
Li, J., Link, M. F., Pandit, S., Webb, M. H., Mayer, K. J., Garofalo, L. A., … Farmer, D. K. (2023). The persistence of smoke VOCs indoors: Partitioning, surface cleaning, and air cleaning in a smoke-contaminated house. Science Advances, 9(41). doi:10.1126/sciadv.adh8263
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