A new study, published in the journal Chemosphere, examined the use of flame retardants in young education environments. Alarmingly, most of the preschools sampled had hazardous particulates in the dust and air samples taken. A key source of hazardous materials is flame retardants, which can contain chemicals that are harmful to children’s health.

The chemicals, which have been linked to hormone disruption and lowered IQs in children, were found in 100 percent of the dust samples collected, reports SF Gate. They included polybrominated diphenyl ethers, or PBDEs, as well as tris phosphate compounds, a non-PBDE flame retardant. Unfortunately, this is not atypical of what is found in most households. These chemicals have been widely used for decades in the polyurethane foam inside upholstered furniture.

The flame retardant chemicals were first added to foam in upholstered furniture in the early 1970s on a widespread basis to meet a state flammability standard that would allow the products to be sold in California. Last year, the Governor ordered that the rules be changed so that the flammability standards can be met without the use of the chemicals. On the other hand, PBDEs have been banned in California for almost a decade. They still exist in older furniture and other products.

After the ban, many manufacturers replaced PBDEs with chlorinated tris. That chemical has been removed from children’s pajamas since 1977 because studies found that exposure to it mutated DNA. Now listed as a carcinogen, it is still found in homes and in child care environments.