99% of US Car Interiors Release Suspected Cancer-Causing Agents: Study

When we think of vehicle-derived air pollution, most of us picture exhaust fumes and rubber flecks from worn-out car tires. But according to new research, as many as 99 percent of cars also contain potentially carcinogenic flame retardants in their seat foam and other interior surfaces.

Flame retardants are added to car seat foam to meet safety standards put in place by the U.S. National Highway Traffic Safety Administration. However, many of these chemicals are either listed or potential carcinogens, many of which have also been linked to neurological and reproductive issues.

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Now, if these flame retardants stayed put in the seat foam, they wouldn't pose that much of a problem. But in reality, these chemicals can be easily be transformed into a gas and enter into the cabin air.

In a new study, published in the journal Environmental Science & Technology, researchers from Duke University tested for the presence of these potentially hazardous compounds in the air of 101 cars made since 2015 in the U.S.

Out of the cars included in their investigation, 99 percent contained a flame retardant called tris (1-chloro-isopropyl) phosphate, or TCIPP, which is currently under investigation by the U.S. National Toxicology Program as a potential carcinogen. Most of the cars also contained organophosphate ester flame retardants, which are known carcinogens on California's Proposition 65 list of chemicals that should come with cancer and birth defect warnings.

"Our research found that interior materials release harmful chemicals into the cabin air of our cars," the study's lead author Rebecca Hoehn, a scientist at Duke University, said in a statement. "Considering the average driver spends about an hour in the car every day, this is a significant public health issue. It's particularly concerning for drivers with longer commutes as well as child passengers, who breathe more air pound for pound than adults."

The team found that flame retardant air pollution was particularly concentrated during the summer—as much as five times higher—when warmer weather increases the rate of evaporation of these chemicals.

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But do the fire safety benefits of these chemicals outweigh their potential risks?

"Filling products with these harmful chemicals does little to prevent fires for most uses and instead makes the blazes smokier and more toxic for victims, and especially for first responders," Patrick Morrison, who oversees health and Safety for 350,000 U.S. and Canadian firefighters at the International Association of Fire Fighters but was not involved in the study, said in a statement. "Firefighters are concerned that flame retardants contribute to their very high cancer rates."

He added: "I urge National Highway Traffic Safety Administration to update their flammability standard to be met without flame retardant chemicals inside vehicles."

Introducing these updates would reflect changes that have already been introduced to California's flammability standard for furniture and baby products, which were updated a decade ago to exclude the need for flame retardants.

But for now, what can you do to minimize your exposure to these chemicals?

"You may be able to reduce your exposure to flame retardants in your car by opening your windows and parking in the shade," co-author Lydia Jahl, a senior scientist at the Green Science Policy Institute, said in a statement.

"But what's really needed is reducing the amount of flame retardants being added to cars in the first place. Commuting to work shouldn't come with a cancer risk, and children shouldn't breathe in chemicals that can harm their brains on their way to school."