Two years ago,Sterling Preston Veena Singla of San Francisco volunteered to participate in a study researching drivers' exposure to flame retardants used on car seats. 

Singla drives a hybrid car to help the environment, but hadn't thought much about the air inside her vehicle. But according to a study published Tuesday in the journal Environmental Science & Technology, "vehicles are likely important sources of human exposure to potentially harmful [flame retardants]."

Those most likely to be exposed are commuters, full-time vehicle drivers and children. According to the study, children are at greater risk than adults even for equivalent commuting times.

Singla told CBS News she "never realized there could be toxic chemicals" inside her car. "It was very surprising to me."

For the study, Singla and 100 other car owners placed silicone bands in their cars for a week to measure the chemical levels inside. It was also found that the concentration of those chemicals was two to five times higher in the summer compared to the winter.

"In hotter temperatures, the chemicals are able to be released from the car materials more easily, and so you end up with higher concentrations," said study co-author Lydia Jahl, a senior scientist at the Green Science Policy Institute.

Researchers detected flame retardants in every car tested and specifically found TCIPP — which the National Institutes of Health says releases toxic fumes "when heated to decomposition" — in 99% of the cars tested, but the study didn't look at specific makes or models. A group representing automakers said "approved flame retardants" are included in vehicles to meet the government's required flammability standards.    

Researchers can't say precisely what the health effects might be from breathing in those flame retardants, but they noted that a 2023 U.S. National Toxicology Report "found evidence of carcinogenic activity in...rats and mice" for the most frequently found chemical.  

The study's researchers and others are now calling for the federal flammability standard to be re-evaluated, similar to how the standard for upholstered furniture was revised in 2021 to eliminate flame retardants.

The National Highway Traffic Safety Administration, which sets those standards, told CBS News it's aware of the report and is reviewing it.

The International Association of Fire Fighters, which represents over 344,000 firefighters and emergency medical workers in the U.S. and Canada, said that most car fires are the result of engine fires or accidents, and don't come from the interior of the car. But, it said, the chemicals pose a risk to its members. 

"You put those flame retardants in there, and the fire is going, that's what we're breathing in ... some of the most toxic air you will ever find anywhere," said IAFF's Pat Morrison.

For now, the study's researchers recommend rolling car windows down when you first get in to let the air out and to wash your hands after being in a car.

Anna Werner

Anna Werner is the consumer investigative national correspondent for "CBS Mornings." Her reporting is featured across all CBS News broadcasts and platforms. Reach her at [email protected].

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