Many car seats sold in the U.S. still contain toxic chemicals though manufacturers have removed some of the most damaging, according to a new report.

Researchers behind the report, published by the non-profit education group The Ecology Center, found toxic chemicals in all 15 cars seats from a variety of brands. The chemicals, which are placed in the seats to act as flame retardants, include materials known to cause cancer, disrupt hormone functioning and harm child development, according to the report.

But despite the alarming news, the report shows that car seat manufacturers have made progress eliminating the worst chemicals. For the first time since the group began testing car seats a decade ago, no car seat contained lead, a chemical with well-documented developmental effects, or chlorinated tris, a chemical thought to have cancer-causing effects. The brands tested include BabyTrend, Britax, Chicco, Clek, Cosco, Diono, Evenflo, Joie, Maxi-Cosi, Nuna, Orbit, Recaro, Safety 1st and two Graco models.

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“It is essential that parents put their kids in properly installed car seats, which provide vital crash protection, regardless of chemical hazard,” says Jeff Gearhart, Ecology Center research director, in a press release. “However, there are some seats that are healthier than others in terms of toxic chemical content.”

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Federal regulations require car seat manufacturers to comply with flammability standards. Researchers behind the report say that manufacturers can comply with that rule without using hazardous flame retardants, but such alternatives would significantly increase the cost of a car seat.

Car seats are just one of many widely-used products including household furniture that contain flame retardants made with toxic chemicals. Household products also contain a slew of other chemicals that similarly cause cancer and contribute to other developmental issues.

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Write to Justin Worland at justin.worland@time.com.