A properly installed car seat can save lives, but experts say the amount of time your child spends in it could put their long term health at risk.

Courtney Hawkins, like many moms, let's her baby sleep in the car seat. "I try to keep him asleep as much as I can, and tiptoe the car seat out of the car and into the house or store," she says. Now researchers say parents should stop doing that after finding cancer causing chemicals and chemicals with unknown side effects in some seats.

"Many of these are hormone disrupters and the impact can be significant," says scientist Jeff Gearhart. Gearhart is part of The Ecology Center, a non-profit environmental organization that first began testing child car seats 10 years ago. He believes the work is incredibly important. "It's a safety device," he says. "You don't have an option to say I'm not going to buy one because I'm concerned about exposure."

RELATED: Ecology Center Study

The idea of adding chemicals in car seats goes back to the 1960's when more people smoked in cars. Car upholstery was treated with flame retardants to keep ashes from igniting the fabric. Children's car seat were then added to federal flammability standards in the 80's without any specific rules on what chemicals can and can't be used. While many of those chemicals are being phased out of clothing and furniture, they're still showing up in car seats. In some cases, manufacturers don't know what chemicals are used.

In 2016, Ecology Center scientists tested 15 popular seats, ranging in price from $50 to $400. For the first time, they found a seat, the Uppababy Mesa Henry, free of any flame retardants. That seat costs around $300 dollars and is unavailable from most websites until spring.

Britax and Maxi-Cosi models also got top marks. Graco, Safety 1st and Evenflo didn't do so well.

RELATED: Lawmaker's bill to reduce the use of chemicals in car seats

Experts suggest parents limit use of car seats for travel only, not napping. They also say keep the seats clean because chemicals can flake off fabrics and find their way into nasal passages and mouths. It's also recommended to wash a child's hands after they're out of the seat.

RELATED: Petition to remove chemicals from car seats

Lawmakers are considering a bill that was introduced last spring that would keep chemicals out of car seats.