Updated

Children at preschools and day care centers in the United States are potentially being exposed to dangerous flame retardant compounds, according to a new study from the University of California, Berkeley.

In 2006, two types of polybrominated diphenyl ethers (PBDEs) – a compound used as a flame retardant – were banned in the state of California over health concerns, such as neurodevelopmental delays in children.  However, furniture containing the chemicals still exists in many buildings.

In a study published in the journal Chemosphere, researchers tested for the presence of 14 PBDEs and four non-PBDE flame retardants – including tris phosphate compounds – in 40 child care centers in California. The facilities served a total of 1,764 children and were located in a mix of rural, urban and agricultural areas.

The researchers discovered both PBDE and non-PBDE flame retardant compounds in 100 percent of the samples tested. The types of furniture found in the facilities may be to blame: 29 facilities had upholstered furniture and 17 had foam napping equipment for children. Facilities utilizing foam equipment had significantly higher levels of PBDEs compared to those without foam products.

"These findings underscore how widespread these materials are in indoor environments," lead author Asa Bradman, associate director of the Center for Children's Environmental Health Research at UC Berkeley, said in a press release. "…Children are more vulnerable to the health effects of environmental contaminants, so we should be particularly careful to reduce their exposure to harmful chemicals."

The California Department of Toxic Substances Control named children’s foam sleeping pads as a product considered harmful to consumers earlier this year.  The presence of non-PBDE tris phosphate compounds was particularly surprising to the researchers, as this compound was named as a presumed carcinogen in 1970.

"I remember learning about the tris phosphate flame retardants in kids' pajamas when I was in high school 35 years ago, so it's a bit surprising to still be seeing them today," said Bradman. "They were never banned. There seems to have been a resurgence in recent years as manufacturers looked for PBDE replacements."

New standards on flame retardants in California aim to minimize health risks associated with exposure to these chemicals.  The policy changes will go into effect this year and become mandatory by January 2015.

"The new standard is not a ban on flame retardants, but manufacturers can meet it without using the chemicals," Arlene Blum, executive director of the Green Science Policy Institute and a UC Berkeley visiting scholar in chemistry, said in a press release. "Most upholstered fabrics, such as leather, are already smolder-proof. Consumers should verify that the furniture they are buying is free of flame retardants, especially when children will be exposed."