Study Chemicals in car interiors may cause cancer — and they’re required by US law (May 2024) Flame Retardant Exposure in Vehicles Is Influenced by Use in Seat Foam and Temperature

Michael Harrop

Active member
Jul 6, 2023

Patrick Morrison, of the International Association of Firefighters, said in a statement on the study that these chemicals do little to prevent blazes — but instead simply make them “smokier and more toxic.”

Flame retardant chemicals off-gas or leach from the seat and interior fabrics into the air, — especially in hot weather, when car interiors can reach 150 degrees Fahrenheit.

health researchers have found that the average U.S. child has lost up to 5 IQ points from exposure to flame retardants in cars and furniture. And adults with the highest levels of flame retardants in their blood face a risk of death by cancer that is four times greater than those with the lowest levels, according to the Journal of the American Medical Association.


Flame retardants (FRs) are added to vehicles to meet flammability standards, such as US Federal Motor Vehicle Safety Standard FMVSS 302. However, an understanding of which FRs are being used, sources in the vehicle, and implications for human exposure is lacking. US participants (n = 101) owning a vehicle of model year 2015 or newer hung a silicone passive sampler on their rearview mirror for 7 days. Fifty-one of 101 participants collected a foam sample from a vehicle seat.

Organophosphate esters (OPEs) were the most frequently detected FR class in the passive samplers. Among these, tris(1-chloro-isopropyl) phosphate (TCIPP) had a 99% detection frequency and was measured at levels ranging from 0.2 to 11,600 ng/g of sampler. TCIPP was also the dominant FR detected in the vehicle seat foam. Sampler FR concentrations were significantly correlated with average ambient temperature and were 2–5 times higher in the summer compared to winter. The presence of TCIPP in foam resulted in ∼4 times higher median air sampler concentrations in winter and ∼9 times higher in summer.

These results suggest that FRs used in vehicle interiors, such as in seat foam, are a source of OPE exposure, which is increased in warmer temperatures.
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