A peer-reviewed study from Duke University and the Green Science Policy Institute has found that 99 percent of car interiors contained a flame retardant under investigation by the U.S. National Toxicology Program as a potential carcinogen.
The study has also discovered that most cars had additional carcinogenic or neurotoxic flame retardants present inside the cabin air.
These chemicals are added to car interiors to meet a 50-year-old NHTSA flammability standard. While car manufacturers add the chemicals to seat foam and other materials to meet the standard, experts have questioned the validity of the standard, seeing it as outdated and with no proven fire-safety benefit.
The expert view is that 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. This has culminated in a campaign to have these chemicals removed.
According to lead researcher Rebecca Hoehn: “Our research found that interior materials release harmful chemicals into the cabin air of our cars. 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 researchers detected flame retardants inside the cabins of 101 cars (model year 2015 or newer) from across the U.S. This revealed that 99 percent of cars contained tris (1-chloro-isopropyl) phosphate (TCIPP), a flame retardant under investigation by the U.S. National Toxicology Program as a potential carcinogen.
Most cars had additional organophosphate ester flame retardants present, including tris (1,3-dichloro-2-propyl) phosphate (TDCIPP) and tris (2-chloroethyl) phosphate (TCEP), two California Proposition 65 carcinogens.
These and other flame retardants are also linked to neurological and reproductive harms.
When a number of cars were tested during the summer and winter, warmer weather was linked to higher flame retardant concentrations because off-gassing from interior components like seat foam is increased by higher temperatures.
Across all seasons, vehicles that contained the suspected carcinogen TCIPP in their foam tended to have higher concentrations of TCIPP in their air, confirming foam as a source of this flame retardant in cabin air.
The research has been published in the journal Environmental Science & Technology. The research is titled “Flame Retardant Exposure in Vehicles Is Influenced by Use in Seat Foam and Temperature.”
