WHO Drops Weak PFAS Guidelines and Starts Anew After Criticism Over Industry Influence

The World Health Organization has scrapped its draft guidelines for "forever chemicals" in drinking water and restarted scientific review following criticism that its previous process was unduly influenced by industry-linked science, The Guardian reported Wednesday.

Leading scientists and public health experts from around the world had for the last two years called on the WHO to reverse course after the organization released draft guidelines they deemed to be far too weak to protect human health. Regulators in the United States and the European Union now have much stricter standards for per- and polyfluoroalkyl substances (PFAS) than those the WHO was proposing.

WHO guidelines are consequential because regulators in many countries use them to set standards, and they can be cited in industry-backed lawsuits that argue that a national or subnational regulatory standard is too strict.

The WHO's reversal was highly unusual and showed the level of scrutiny its PFAS process was under, experts said.

"This is unprecedented, but the WHO got unprecedented criticism," Betsy Southerland, the former director of science and technology at the U.S. Environmental Protection Agency (EPA) Office of Water, told The Guardian.

Southerland herself was one of the leading critics. Last year, she and Linda Birnbaum, the former director of the U.S. National Institute of Environmental Health Sciences, wrote a commentary in Environmental Science & Technology, a peer-reviewed journal, in which they called the WHO's approach "stunning" and argued for extensive revision of the guidelines.

In November 2022, a group of more than 100 scientists wrote an open letter to the WHO calling for a reconsideration of the guidelines to include the raft of research on the dangers of PFAS to human health, more transparency about the process, and better enforcement of the organization's conflict-of-interest policy.

PFAS are a class of roughly 16,000 synthetic compounds that were developed by the chemical industry, including companies such as 3M and DuPont, in the mid-20th century. The compounds, which are called forever chemicals because they break down only very slowly, are found in many household and industrial products and are now found in the blood of most humans, raising public health concerns because their links to many types of cancer and other diseases.

Two of the most well-known and well-studied PFAS are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), and it's these two compounds that have been the focal point of the WHO rulemaking process. The WHO proposed guidelines of limits of 100 parts per trillion for the two compounds—well above the 4 ppt the EPA recently instituted, based on research showing there was "no safe level of exposure" to the contaminants—citing unclear research and inadequate filtration systems for PFOA and PFOS removal at very low levels.

Critics said those arguments came from flawed reasoning and research. For example, the WHO had, in a key document, repeatedly cited the work of Michael Dourson, a controversial toxicologist whom then-President Donald Trump had named to lead the EPA's chemical safety division in 2017 but who ultimately ended up in another position, due to criticism over his ties to industry. The New York Times that year published emails Dourson had exchanged with the American Chemistry Council, a lobby group, that showed a close relationship.

Dourson told The Guardian that the work that he and other scientists whom the WHO cited in its 2022 draft guidelines did was independent of industry influence and that the guidelines had been sound, given the uncertainty about PFAS science.

But Birnbaum told the newspaper that invoking uncertainty and casting doubt on the science is an industry tactic. That's one of the approaches being used in legal challenges to the EPA's stricter rules.