New studies of common flame retardants link these chemicals to mental impairments in young children and cancer in firefighters.

Children exposed to common flame-retardant chemicals before birth have a greater risk of hyperactivity and lower IQ scores, according to new research presented at a meeting of the Pediatric Academic Societies in Washington D.C.

This group of brominated chemicals, called polybrominated diphenyl ethers (PBDEs), were mostly withdrawn from the American market in 2004 and are no longer used as flame retardants in the U.S. However, they were used for decades in things like furniture foam, carpeting, plastics, baby strollers, and electronics.

Because the chemicals are not bound to the products they are used in, they are more likely to leach into the surrounding air, water, and soil. PBDEs have been found in fish, as well as in human blood and breast milk, according to the U.S. Environmental Protection Agency (EPA).

Though outlawed, the chemicals remain in U.S. products manufactured before 2004. The chemicals do not biodegrade easily, so if they are ingested or absorbed they remain in the body and can be transferred to a developing fetus, the researchers said.

And there are still many legal flame-retardant chemicals used in furniture and other home goods that pose huge health risks to humans, according to Charles Margulis, communications director for the Center for Environmental Health (CEH, which aims to eliminate the use of all flame-retardant chemicals in home furnishings and other products.

Also according to the CEH, there may be as much as two pounds worth of chemicals meant to prevent fires in a single living room couch, and flame-retardants have even been found in mats at a daycare center.

“I doubt there are many children smoking during nap time at a daycare,” Margulis said in an interview with Healthline. “There’s study after study that these chemicals are harmful and ineffective in preventing fires. They’re causing serious health problems and they’re incredibly prevalent.”

Dr. Aimin Chen, an assistant professor at the University of Cincinnati College of Medicine’s Department of Environmental Health, analyzed blood samples from 309 pregnant women and performed intelligence and behavioral tests on the mother’s children until they reached 5 years old.

Chen’s team found that a mother’s exposure to PBDEs was associated with reduced cognition in her 5-year-old and symptoms of hyperactivity as early as age 2. A 10-fold increase in a mother’s PBDE exposure was associated with a four-point IQ deficiency in her 5-year-old, Chen reported.

“Because PBDEs exist in the home and office environment as they are contained in old furniture, carpet pads, foams and electronics, the study raises further concern about their toxicity in developing children,” Chen said in a press release.

Previous research from the Centers for Disease Control (CDC) has shown that PBDE levels are “considerably higher” in Americans than in Europeans.

The EPA states that major concerns about PBDEs include evidence of liver toxicity, thyroid toxicity, and neurodevelopmental toxicity.

“It’s very hard to tell if products contain certain flame-retardant chemicals,” Margulis said. “There’s no requirements for labeling.”

When fire-retardant chemicals don’t retard fire, they’re released into the air during a blaze. Those who rush into the burning building may then have a greater risk of developing cancer and other health conditions.

A new study by environmental toxicologist Dr. Susan Shaw and colleagues shows that firefighters have a greater risk of exposure to PBDEs when furniture, televisions, and other home furnishings are engulfed in a house fire.

Studying San Francisco firefighters, the researchers found that brominated dioxin and furans concentrations were 21 times more toxic than other chemicals commonly encountered when battling a blaze.

“Firefighters have much higher levels and different patterns of these chemicals in their blood than the general population,” Shaw said in a press release. “What we have shown here points to the possible link between firefighting and cancer.”