Indoor dust contains dangerous, endocrine-disrupting chemicals, according to a study published today in Environmental Health Perspectives. The study of 46 dust samples from 21 buildings at a U.S. university found that all 46 samples contained hormonally active compounds that can lead to health effects, including infertility, diabetes, obesity, abnormal fetal growth, and cancers.
The study helps explain how industrial chemicals known as PFAS and flame retardants, which are found in the blood or urine of over 90 percent of Americans and are already known to cause widespread health and reproductive effects, enter the body. PFAS, which first came to light as ingredients in Teflon, are also used to coat carpets, furniture, and clothing. Despite a lack of evidence that they prevent fires, flame retardants are added to furniture, carpet, electronics, and building insulation. While we don’t eat these products, this study makes it clear that we breathe in tiny bits of them that have entered the air as dust.
“We don’t realize we’re taking this dust into our bodies all day every day,” said Anna Young, a postdoctoral research fellow in the Department of Environmental Health at the Harvard T.H. Chan School of Public Health and lead author of the study. According to Young, people ingest an average of 20 milligrams of dust each day.
While the health effects of PFAS and flame retardants have been known for years, the Environmental Protection Agency has been ineffective at curbing exposure to the chemicals. One class of flame retardants found in the dust — polybrominated diphenyl ethers, or PBDEs — was phased out in 2013 after they were found to cause infertility, thyroid dysfunction, and other health problems. But those compounds remain in many products and have been recycled into many others. Meanwhile, a class of chemicals now used to replace PBDEs, organophosphate esters, has also been found to cause reproductive problems, impair behavioral and cognitive development, and lead to pregnancy loss.
The health effects of PFAS are also well known and include impaired fetal development, obesity, decreased vaccine response, preeclampsia, testicular cancer, immune dysfunction, kidney cancer, and elevated cholesterol levels. But while two compounds in the class, PFOA and PFOS, were voluntarily phased out as of 2015, those two compounds remain in many products, and thousands of other PFAS, including some that present clear health dangers, are still in use.
“They’ve shown there’s a lot of bioactivity in dust,” Linda Birnbaum, former director and scientist emeritus of the National Institute of Environmental Health Sciences and the National Toxicology Program, said of the study’s authors. “People don’t understand that we are being exposed all the time to a multitude of chemicals that impact our endocrine systems. Things that are in our products don’t stay put. They get into our dust, whether house or office dust. And if they get into our house or office dust, they get into us.” Birnbaum pointed out that the study didn’t look for many other chemicals that have already been found in dust, including PCBs, heavy metals, pesticides, and phthalates.
While regulators have so far failed to prevent exposure to the PFAS and flame retardants that were identified in the study, some companies have begun to get rid of these chemicals on their own. In 2016, Ikea phased out textiles that contain PFAS. Three years later, the Home Depot stopped purchasing and distributing carpets that contain the chemicals. In 2020, Lowe’s made a similar commitment. Furniture makers have also begun to make couches and chairs without flame retardants.
A study by Young published last year showed that dust in rooms where furniture and rugs that were free of these chemicals contained lower levels of the contaminants. Consumers concerned about the toxicity of their homes can check out the quickly evolving list of PFAS-free products. And people worried about whether their couches contain flame retardants can even send samples to scientists at Duke University, where scientists will test them to see if the chemicals are present.
But making indoor air safe to breathe will ultimately require regulatory action. “It can’t be on consumers to figure out what products are safe when there are thousands of these chemicals and manufacturers don’t have to disclose them,” said Young. “We need to send the market a signal that we want healthy products to be the default and not the exception.”