The air in your car could be carcinogenic: study

When it comes to your commute, a traffic jam might be the least of your worries.

The air inside your car may be filled with potential carcinogens in the form of flame retardant chemicals, a new study has found. 

Researchers, who published their findings in the journal Environmental Science and Technology on Tuesday, detected flame retardants inside the cabin of 101 cars, all from models dated 2015 or newer. 

Manufacturers use such flame retardants in seat foam and other interior materials, to meet an “outdated federal flammability standard with no proven fire-safety benefit,” the authors of the study argued in a statement. 

“Considering the average driver spends about an hour in the car every day, this is a significant public health issue,” lead author Rebecca Hoehn, a scientist at Duke University, said in a press release. “It’s particularly concerning for drivers with longer commutes as well as child passengers, who breathe more air pound for pound than adults.”

Among the cars tested, 99% contained a chemical known as tris (1-chloro-isopropyl) phosphate, which is a flame retardant now under investigation by the U.S. National Toxicology Program for being a potential carcinogen. Other chemicals found included tris (1,3-dichloro-2-propyl) phosphate and tris (2-chloroethyl) phosphate — which are two chemicals known to be carcinogenic under California’s Proposition 65, which has banned the sale of new products that contain these chemicals since 2020.

Researchers tested the seat cushion foam and found that cars that contained the chemical TCIPP in their foam had higher concentrations in the cabin air, showing that the source was from the flame retardant used to treat the foam itself. 

The study also examined cars in summer and winter and found that temperature had an impact on the air quality. Warmer weather was linked to higher off-gassing of the chemicals, because of the high temperatures. As many people know, car interiors can rapidly get hot even when it’s not too hot outside. On a day when it’s 80 F, for example, after just 20 minutes in the sun, a car’s interior temperature can reach 109 F.

Researchers hope that their findings will encourage the so-called outdated flammability standards to be updated, so manufacturers will stop using these chemicals. 

“The only surefire way to drastically reduce exposure would be for flame retardants not to be added in the first place, which will require [the National Highway Traffic Safety Administration] to update its standard,” Dr. Lydia Jahl, senior scientist at the Green Science Policy Institute in Berkeley, California, told The Post.  

Those looking to reduce their exposure should keep the car well ventilated by keeping the windows open whenever possible and parking in the shade. Jahl also noted that, to her knowledge, there have been no studies showing that things like car seat covers (plastic or otherwise) will help reduce exposure. Cleaning your car regularly could help, she proposed, especially if you have small children.

“Ensuring plenty of ventilation through open windows and limited use of recirculated air mode are the easiest ways to reduce exposure,” Jahl advised.

Jahl also noted that it didn’t matter if a car was older or newer — the harmful fumes being released into the air stuck around for years.

“What’s problematic about flame retardant usage in seat foam and other materials is that the tiny amounts that off-gas over time can contribute to our exposure while still leaving plenty of flame retardant chemicals in the materials for years to come,” Jahl warned.

Jahl said that those looking to buy the “safest” car in this regard unfortunately won’t be able to avoid the flame retardants entirely because of the current standards.

Researchers hope their findings will encourage the National Highway Traffic Safety Administration to update their standard regarding the use of flame retardants. 

The NHTSA told The Post via email they are aware of this report and are reviewing it.