Study Reveals Health Risks from Flame Retardants in Car Interiors

In the United States, cars use flame retardants within seat foams and other areas of vehicle cabins which is linked to health concerns such as neurological issues, hormone disruption, and cancer-related death. 

The researchers from Duke University and the Green Science Policy Institute also discovered air flame retardant levels were two to five times higher in vehicle cabins in the summer compared to winter. This study published in the journal Environmental Science & Technology recruited 101 US citizens who own a car with a model year of 2015 or newer to hang a silicone passive sampler on their rearview mirror for seven days. 

A silicon passive sampler can be used to measure different types of pollutants in the air, including brominated and organophosphate flame retardants. 

It was reported that organophosphate eaters were the most frequently detected fire retardant collected by the silicone passive samplers.OPEs are increasingly used as both flame retardants and plasticizers — i.e. chemicals that change the properties of plastics — in various materials. Car interiors often contain a large proportion of plastic components that are likely sources of these OPEs, such as the foam in the interior roof lining, the seats, the electronics in the dashboards, etc. The more plastics people surround themselves in their daily lives, the more exposure they will have to these chemicals, particularly inside a car interior where the space is relatively small compared to a home or building. 

Of OPEs, tris(1-chloro-isopropyl) phosphate (TCIPP) had a 99% detection frequency with in-cabin air measurements ranging from 0.2 to 11,600 ng/g of sampler. Researchers and their team found that TCIPP was the dominant fire retardant discovered in car seat foam. 

TCIPP is a chlorinated organophosphate flame retardant that has been used extensively in some textiles, building insulation, and furniture. It has been increasingly used following the phase-out of another close chemical TDCIPP, which is considered a probable human carcinogen. 

Half of the cars included in the study were tested both during the summer and winter. Fire retardant concentrations within vehicle cabins were two to five times higher in summer than in the winter. The presence of TCIPP in foam resulted in about four times higher average air sampler concentration in winter and almost nine times during summer months.  

Chemicals are emitted from plastics at higher rates with higher temperatures. Therefore, levels of these chemicals in the cabin air of a vehicle will be higher in cars parked or residing in warm areas of the country vs cars in colder parts of the country. People entering these cars will be breathing in this air with higher concentrations of flame retardants and receiving higher exposures 

Researchers hope this brings more attention to the use of these chemicals in personal vehicles and the risks they potentially pose to human health. There are no research studies that prove the use of these chemicals in car seats helps to save lives. In contrast, data shows that the presence of flame retardant chemicals in seat foam leads to the generation of more smoke and toxic chemicals like carbon monoxide and hydrogen cyanide when they burn during a fire. 

It’s also important to note that these chemicals do not stop materials from burning, they only slow the rate at which they burn, and while they burn they are creating dangerous conditions i.e. more smoke and toxic chemicals.