A recent study published in Environmental Science & Technology has revealed that the air inside personal vehicles is contaminated with harmful flame retardants, some of which are known or suspected to cause cancer. These chemicals, which are added by car manufacturers to meet an outdated federal flammability standard, have no proven fire-safety benefit. The research raises significant concerns about public health, particularly for individuals with longer commutes and child passengers who spend a significant amount of time in cars.

The study, led by scientist Rebecca Hoehn from Duke University, examined 101 cars from across the United States, all of which were model year 2015 or newer. Astonishingly, 99% of the vehicles tested contained tris (1-chloro-isopropyl) phosphate (TCIPP), a flame retardant currently under investigation by the U.S. National Toxicology Program as a potential carcinogen. Many cars also contained other organophosphate ester flame retardants, including tris (1,3-dichloro-2-propyl) phosphate (TDCIPP) and tris (2-chloroethyl) phosphate (TCEP), both of which have been classified as California Proposition 65 carcinogens and are associated with neurological and reproductive harms.

The study revealed that warmer weather was linked to higher concentrations of flame retardants, as higher temperatures increased the off-gassing from interior components like seat foam. Interior temperatures in vehicles can reach up to 150 degrees Fahrenheit, exacerbating the release of these harmful chemicals into the cabin air.

Further analysis of seat foam samples from 51 of the tested cars confirmed that foam was a significant source of flame retardants in the cabin air. The presence of the suspected carcinogen TCIPP in the foam correlated with higher concentrations of TCIPP in the air.

The use of flame retardants in seat foam is mandated by the U.S. National Highway Traffic Safety Administration (NHTSA) Federal Motor Vehicle Safety Standard (FMVSS) 302, an open-flame flammability standard that has remained unchanged since the 1970s. Firefighters, who are already at a heightened risk for cancer, have expressed concerns about the contribution of flame retardants to their high cancer rates. Patrick Morrison, overseeing Health and Safety for 350,000 firefighters at the International Association of Fire Fighters, urged the NHTSA to update the flammability standard to eliminate the need for flame retardant chemicals in vehicles.

The study highlighted a parallel with California's flammability standard for furniture and baby products, which underwent an update a decade ago to a modern standard that does not require flame retardants. This update has not only maintained or increased furniture fire safety, but has also led to lower levels of flame retardants in American homes.

Previous epidemiological studies have revealed that exposure to flame retardants used in cars and furniture has led to a loss of three to five IQ points in the average U.S. child. Additionally, recent research has linked higher levels of this flame retardant in the blood to a fourfold increase in the risk of dying from cancer compared to individuals with lower levels.

While opening windows and parking in the shade may help reduce exposure to flame retardants in cars, co-author Lydia Jahl, a senior scientist at the Green Science Policy Institute, emphasized the necessity of reducing the amount of flame retardants added to vehicles. The goal is to ensure that commuting and traveling in cars do not pose unnecessary cancer risks and that children are not exposed to chemicals that could harm their developing brains.

The findings of this study shed light on an urgent public health concern and call for updated regulations to protect individuals from harmful flame retardant exposure.