Child Car Seats Pose a Little-Known Cancer Risk

• A study has shown that nearly all cars driven today contain a suspected carcinogen, added to seat foam as a flame retardant. The danger is made worse in that the same chemical is used in child car seats.

• The motivation behind the use of such a chemical is the mitigation of the risk of cabin fire caused by smoking in the car, something that doesn’t happen with near the same frequency as it did when the federal standard was enacted.

• A trio of legislators have sent a letter to the National Highway Traffic Administration declaring their alarm at the results of the study.

A recent study of late-model cars found the suspected carcinogen TCIPP in almost all—99%—of the 101 vehicles tested from 22 manufacturers. Known carcinogens were found, too, as well as endocrine disrupters and neurotoxins. Two of the chemicals found are on California’s Proposition 65 List as causing cancer.

The culprit is the flame retardants added to meet a federal standard for seat foam and other components. But are seat fires—often caused by smoldering cigarettes—still as big an issue these days?

An August 7 letter to the National Highway Traffic Safety Administration from Senator Richard Blumenthal (D-CT) and two House members, Doris Matsui (D-CA) and H. Morgan Griffith (R-VA), cited the politicians’ “alarm” at the results of the study.

“We are concerned that consumers could be unknowingly exposed to these harmful flame-retardant chemicals in their vehicles,” the letter said, blaming an “outdated” federal standard. The letter said the FMVSS 302 standard dates to a time when people often smoked in their cars.

“Today far fewer people smoke in their cars, and less than 10% of vehicle fires are caused by an open flame,” the letter said. It called on NHTSA Deputy Administrator Sophie Shulman to “review the underlying standard to ensure it protects consumers from both fires and harmful chemicals in their vehicles.”

Congressman Griffith told Autoweek, “What our letter to NHTSA simply does is ask the agency to review its federal flammability standards for vehicles. I am interested to see how the agency evaluates its standards.” The two other Congressional signatories to the letter were not available for comment at press time.

Organophosphate ester (OPE) flame retardants are commonly used in today’s vehicles, as well as in home furnishings, textiles, and electronics.

Researchers from Duke University, the University of Toronto and the Green Science Policy Institute published their study in Environmental Science and Technology last May. “These results suggest that flame retardants used in vehicle interiors, such as in seat foam, are a source of organophosphate ester (OPE) exposure, which is increased in higher temperatures,” the study said.

According to the report, “Studies have now shown that exposure to certain OPEs is associated with altered birth outcomes, reproductive harm, and carcinogenicity. A well-known OPE, TDCIPP, has been associated with negative health effects, including decreased fertility, altered thyroid hormone function and cancer.”

A study of 6,646 pregnant participants, published in Environmental Health Perspectives in January of this year, found that “greater prenatal exposure to several OPEs related to elevated risks of preterm birth and shorter gestational age, especially among female newborns.”

Consumer Reports issued a petition to “get cancer-causing chemicals out of cars.” It said, in part, “Manufacturers add these chemicals to seat foam and other materials—including those in children’s car seats—to meet an outdated 1971 federal flammability standard with no proven fire-safety benefit.” The petition got more than 32,000 signatures, which were delivered to NHTSA in June.

It’s not just adults that are at risk. The Ann Arbor, Michigan-based Ecology Center published a study in 2022 that said “more than half of US children’s car seats still contain hazardous chemicals such as flame retardants…A number of flame retardants are known endocrine disruptors.” The center tested more than 600 components of 25 car seats, three from the European Union and 22 from the US.

According to Jeff Gearhart, research director of the Ecology Center, “We got many requests from parents asking about car seats, and we started working with the manufacturers on the issue in the late 1990s. Since then, a whole slew of companies have eliminated the use of flame retardants and are still able to comply with the standard.

“It’s become a marketing claim. A solution is to use denser upholstery materials, but using them results in a more expensive seat. And that’s become an affordability issue at the lower end of the market.”

Gearhart said that meetings with the car seat manufacturers and NHTSA have so far not been productive. “The children’s car seat industry has been frustrated by the unwillingness of NHTSA to take this up,” he said.

In response to the Congressional inquiry, the federal safety agency said only, “NHTSA has received the [Congressional] letter and is reviewing it.” The Alliance for Automotive innovation, representing many automakers, said in response to last May’s joint study, “Automakers are committed to sustainability and include approved flame retardants in all passenger vehicles to meet the flammability standards required by the federal government.” That, we knew.

Do car seats actually need to have flame retardants in them? Dr. Lydia Jahl, a senior scientist at the Green Science Policy Institute, says probably not.

“The standard says that the interior of the car has to withstand an open flame, and for the manufacturers it’s easiest to just add flame retardants,” Jahl said. “This federal standard looks good on paper, but NHTSA doesn’t have the data to prove its efficacy.

“The bottom line is that the standard is 53 years old, and needs to be updated to one with proven fire safety benefit that can be achieved without the use of harmful chemicals.”

Jahl also said that children’s car seats could simply be exempted from the standard. “Six-month olds are not going to be smoking,” she said, adding that it’s not possible to simply replace OPEs with “safer” flame retardants. “There aren’t any flame retardants that really are safer, just some that are less studied,” she said. “Their chemical properties are similar to those known to be carcinogenic.”