As fires sweep across Los Angeles County, destroying restaurants, businesses and entire homes, it's clear that the threat of urban fires is back in the United States. But this time, the urban landscape is different: Modern homes are filled with plastic, turning house fires into chemical-filled infernos that burn hotter, faster, and more toxically than before.
Firefighters warn that the smoke billowing from Southern California communities is a toxic stew, in part due to the ubiquity of plastics and other petrochemicals. “That’s one of the reasons why we can’t send firefighters to these houses,” Cal Fire Capt. David Acuna told me Monday. It is too risky to allow firefighters to continue to live in toxic air after any life-saving work is completed.
There are very few fixtures in modern homes that are completely plastic-free. If your sofa is like many on the market today, it is made from polyurethane foam (plastic) wrapped in polyester fiber (plastic). When polyurethane foam burns, it releases hydrogen cyanide gas, which can be fatal. Perhaps these plastic-wrapped plastic pads sit on a solid wood frame, or perhaps the frame is made of engineered wood products held together with polymer glue (plastic). Consider also the ubiquitous vinyl plank flooring, popular for its wear resistance, and vinyl siding, praised for its durability. Then there’s foam insulation, laminate countertops, and many of the synthetic textiles in our bedding, curtains, and carpets. Almost all house paints on the market can be thought of as pigments suspended in liquid plastic.
Research has long shown that exposure to tiny particles in wildfire smoke poses significant health risks. As I’ve written before , wildfire smoke causes thousands of premature deaths each year and is linked to a range of illnesses. Burning trees release gases such as carbon monoxide and carbon dioxide, as well as tiny solid particles called PM2.5, which can penetrate deep into a person's lungs and circulate in the bloodstream and have been linked to heart and lung problems, low birth weight, premature birth and cognition obstacle. Nadine Bauduas-Dedkin, an atmospheric chemist at the University of British Columbia, told me that burning towns absorb many of the chemical hazards of burning forests and add a new set of hazards. When structure fires engulf large amounts of materials within a home, they release not only hydrogen cyanide gas, but also hydrochloric acid, dioxins, furans, aerosolized phthalates, and a host of other gaseous pollutants, commonly known as For volatile organic compounds. Some may be harmless. Others are related to health issues. As gas detection technology advances, "we are discovering new molecules of incomplete combustion that we didn't know existed," says Bauduas-Dedekind. "When you burn down a house or an entire neighborhood, we have no control over the extent of the volatile organic compounds that are emitted." Many of these substances can react with each other in the atmosphere, creating more compounds. While N95 masks can effectively filter out the fine particles associated with fire smoke, they have no effect on these gases; only respirators can filter them out.
Plastic is made from petroleum, which burns fast and hot. A retired Maryland fire captain told newsweek From a fire perspective, a typical couch resembles a lump of gasoline. Acuna asked me to consider putting a log on the campfire: it takes some time to heat up and char first. It will eventually ignite and turn into a steady flame, releasing heat at a slow, consistent rate over 20 minutes. If you throw a two-liter soda bottle onto a campfire (which is a very bad thing to do), it will immediately start to deform. It ignites within seconds and burns quickly.
In 2020, the Fire Safety Institute deliberately set fire to two living rooms. Both are the same size and have the same furniture arrangement. But in one room, almost everything is synthetic: A polyurethane foam sofa covered in polyester fabric sits behind an engineered wood coffee table, both of which sit atop a polyolefin rug. The curtains were polyester and the couch was covered with a polyester blanket. In another room, a wooden sofa with cotton padding sits on the hardwood floor, along with a solid wood coffee table. The curtains and blankets are made of cotton. In a room with natural materials, a cotton sofa appears to ignite easily and then maintain a steady flame where it is lit, releasing very little smoke. After 26 minutes, the flames had spread to the other side of the couch, but the rest of the room was still intact except for the black smoke. Meanwhile, in the synthetic room, a thick plume of black smoke rose from the flames on the polyester couch. In less than five minutes, a flash of orange flames engulfed the entire room. Firefighters call this a "flash fire" when escape becomes impossible. In the natural materials room, the flashover lasted for more than 30 minutes. Perhaps this difference helps explain why, even though the rate of home fires in the United States has dropped by more than half since 1980, more people die in their homes when fires occur.
When I spoke with Cal Fire's Acuna, he was sitting in his office taking calls from reporters. He looked around the room. "I'm trying to find any natural materials right now. In fact, the only thing I can find is my notebook," he said. Plastics undoubtedly have a use, he added. But it also comes with obvious risks. One day, if there's a fire, "it's going to burn faster and hotter." Strengths will turn into threats.