A new study that checked American women’s breast milk for PFAS contamination detected the toxic chemical in all 50 samples tested, and at levels nearly 2,000 times higher than the level some public health advocates advise is safe for drinking water. The findings “are cause for concern” and highlight a potential threat to newborns’ health, the study’s authors say. “The study shows that PFAS contamination of breast milk is likely universal in the US, and that these harmful chemicals are contaminating what should be nature’s perfect food,” said Erika Schreder, a co-author and science director with Toxic Free Future, a Seattle-based non-profit that pushes industry to find alternatives to the chemicals. PFAS, or per and polyfluoroalkyl substances, are a class of about 9,000 compounds that are used to make products like food packaging, clothing and carpeting water and stain resistant. They are called “forever chemicals” because they do not naturally break down and have been found to accumulate in humans. They are linked to cancer, birth defects, liver disease, thyroid disease, plummeting sperm counts and a range of other serious health problems. The peer-reviewed study, published on Thursday in the Environmental Science and Technology journal, found PFAS at levels in milk ranging from 50 parts per trillion (ppt) to more than 1,850ppt. There are no standards for PFAS in breast milk, but the public health advocacy organization Environmental Working Group puts its advisory target for drinking water at 1ppt, and the federal Agency for Toxic Substances and Disease Registry, within the Department of Health and Human Services, recommends as little as 14ppt in children’s drinking water. Though researchers are concerned by the findings, newborns are difficult to study so there has not been a thorough analysis of how PFAS affect them, said Sheela Sathyanarayana, a co-author of the study and pediatrician with the University of Washington. But she added that studies of older children and adults have linked the chemicals to hormonal disruptions and suggests PFAS harm the immune system, which could be especially problematic for infants because breast milk bolsters their immune system. Though the study checked a relatively small sample size, the contamination cut across socioeconomic and geographic groupings, which is “what makes the issue so difficult on an individual level”, Sathyanarayana said. “What it speaks to is that the chemicals are so ubiquitous that we can’t really predict who will have the highest exposures,” she added. The study also runs counter to a chemical industry claim that its newer generation of PFAS that are still in use do not accumulate in humans. It found more than 12 kinds of compounds in about half of the samples, and 16 compounds overall, including several that are currently in use. Evidence also suggests that the problem is getting worse. The study is the first in the US since 2005 to check breast milk samples, and shows an increase in the newer generation of PFAS, while older compounds that were phased out by industry are still present, and some at high levels. The study also analyzed breast milk data from around the world and found PFAS detection frequency is increasing. Among steps that the authors recommend pregnant women and mothers take to protect themselves are avoiding greaseproof carryout food packaging, stain guards like ScotchGard, waterproof clothing that uses PFAS, and cooking products with Teflon or similar non-stick properties, though manufacturers often do not disclose the chemicals’ use. Moreover, the compounds’ ubiquity makes them all but impossible to avoid, and Schreder said that the best solution is a virtual ban of the entire chemical class, including those that industry claims do not accumulate as much in humans. “The study provides more evidence that the PFAS that companies are currently using and putting into products are behaving like the ones they phased out, and they’re also getting into breast milk and exposing children at a very vulnerable phase of development,” she said.