Daily commuters may be breathing in potentially cancerous air from the car interiors. According to a new study, flame retardants used in car seats and other materials to meet an outdated federal flammability standard raise the risk of exposure to potentially cancerous air, particularly in summer when temperatures are high.

Flame retardants (FRs) are used in vehicles to meet the U.S. Federal Motor Vehicle Safety Standard FMVSS 302. However, considering the harmful health effects, the researchers of the latest study urge the government to update the current regulations to prohibit the use of flame retardants in cars.

To estimate the air quality of car cabins, researchers tested 101 cars across 30 states with a model year between 2015 and 2022. Around 99% of the samples had Tris(1-chloro-isopropyl) phosphate (TCIPP), a common flame retardant class currently under investigation by the National Toxicology Program as a potential carcinogen.

"TCIPP was detectable in 99% of vehicles, and vehicle foam was identified as a source of this compound. The frequent detection of TCIPP in vehicles is particularly concerning given that a 2023 United States National Toxicology Report found evidence of carcinogenic activity in male and female rats and mice exposed to TCIPP, with observed increases in liver adenomas, liver carcinomas, and uterine adenomas or adenocarcinomas," the researchers wrote in the study published in Environmental Science and Technology.

According to Patrick Morrison at the International Association of Fire Fighters who oversees Health and Safety for 350,000 U.S. and Canadian firefighters, the use of flame retardants does not serve the purpose and raises concerns about health risks among firefighters.

"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. I urge NHTSA (National Highway Traffic Safety Administration) to update their flammability standard to be met without flame retardant chemicals inside vehicles," Morrison said in a news release.

Who is at risk?

Commuters, particularly those with longer commutes or those who drive vehicles full time as part of their jobs, are at higher risk, according to the study. Even with equal commuting time, children will face greater risk as they breathe a greater amount of air per kg body weight compared to adults. The risk is also high for those living in warmer climates.

"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," said lead author Rebecca Hoehn, a scientist at Duke University.

However, further studies are needed to estimate the risk as the level of exposure is greatly influenced by personal behaviors such as if the commuter uses climate control or rolls down the window while traveling.

How to reduce risk?

Controlling the vehicle's cabin temperature by parking in the shade is one way to reduce the release of FR into the cabin air. After getting into the parked car, ensure proper ventilation by opening vehicle windows. While switching on air conditioning, avoid frequent recirculation of the interior air to reduce the risk.

According to the researchers, the most effective way is to cut the use of flame retardants, which means the National Highway Traffic Safety Administration has to make changes to their safety standards set in 1970.

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

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