Energy & Environment

Chemicals in car interiors may cause cancer — and they’re required by US law: Study

This is a the interior of a 2024 Corvette Z06 Convertible 3LZ on display at the Pittsburgh International Auto Show in Pittsburgh, Feb. 15, 2024. (AP Photo/Gene J. Puskar)

Tens of millions of Americans each day breathe in carcinogenic chemicals that are woven into the interiors of their cars, a new study has found.

While opening a window can help reduce the risk, only reforms can keep people safe, researchers wrote in a study in Environmental Science and Technology.  

Approximately 124 million Americans commute each day, spending an average of an hour in their cars.

By federal law, the interior of these vehicles are required to contain flame retardants, or chemicals that make it harder for them to combust in a crash.

These chemicals have been a legally mandated part of modern cars since the 1970s, when the National Highway Traffic Safety Administration (NHTSA) passed a law requiring their use.

It’s arguable how effective this protection is. 

Patrick Morrison, of the International Association of Firefighters, said in a statement on the study that these chemicals do little to prevent blazes — but instead simply make them “smokier and more toxic.” 

What the study conclusively demonstrates is that any such protection comes at a price. 

Virtually all cars investigated by Duke University researchers contained the chemical tris (1-chloro-isopropyl) phosphate, or TCIPP — which the U.S. National Toxicology Program is investigating as a potential carcinogen.

Most cars also had two other phosphate-based flame retardants that the state of California is investigating as potential carcinogens: Those chemicals are tris (1,3-dichloro-2-propyl) phosphate (TDCIPP) and tris (2-chloroethyl) phosphate (TCEP).

All three chemicals are linked to reproductive and neurological problems — particularly because they don’t stay in the fabrics they’re woven into.

 Flame retardant chemicals off-gas or leach from the seat and interior fabrics into the air, — especially in hot weather, when car interiors can reach 150 degrees Fahrenheit.

Advocates argue that the risks of these chemicals outweigh the benefits. 

But health researchers have found that the average U.S. child has lost up to 5 IQ points from exposure to flame retardants in cars and furniture. And adults with the highest levels of flame retardants in their blood face a risk of death by cancer that is four times greater than those with the lowest levels, according to the Journal of the American Medical Association.

Morrison, of the firefighters advocacy group, added that “firefighters are concerned that flame retardants contribute to their very high cancer rates.”