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– The U.S. Environmental Protection Agency on Friday proposed new testing methods that will eventually measure the toxicity of five additional kinds of per- and polyfluoroalkyl substances, known collectively as PFAS. They are often called "forever chemicals" because they remain in the body for years.

Earlier incarnations of PFAS have been linked to cancer, high cholesterol, immune deficiencies, liver problems and reproductive issues. Two specific substances, PFOA and PFOS, are at the center of a national water pollution scandal that has led to contamination of water systems and private wells across the country.

In 2018, Maplewood-based 3M, a major producer of PFAS, settled a pollution suit with the Minnesota attorney general's office for $850 million.

The company still faces PFAS pollution suits in multiple states and localities, as well as class action personal injury suits and shareholder suits all charging that the company knew of health risks of PFOA and PFOS for decades before finally discontinuing their use in 2002.

Now, the company could face more questions about its use of the five PFAS as the EPA will test for links to "both cancer and noncancer effects, including potential effects on the endocrine, hepatic, urinary, immune, developmental, and reproductive systems."

At this point, EPA is seeking public comments on its proposed evaluation methods for the five commercial versions of PFAS. The five include perfluorodecanoic acid (PFDA), perfluorononanoic acid (PFNA), perfluorohexanoic acid (PFHxA), perfluorohexanesulfonate (PFHxS), and perfluorobutanoic acid (PFBA).

"PFBA is the only compound that currently has commercial relevance for 3M," a company spokeswoman told the Star Tribune.

She added that "3M supports appropriate science-based regulation of PFAS and believes a consistent and unified federal policy based on sound science can help avoid the cost and confusion of a state-by-state patchwork of regulations. We are pleased to see the U.S. EPA take the next step in this process."

In congressional testimony and lawsuit defenses, the company maintains that PFAS have not caused injury to humans at the levels at which the chemicals appear in the environment.

The company also believes PFAS must be tested individually for toxicity and not regulated as a group.

Public health advocates have criticized the pace at which EPA has sought to measure and limit the use of PFAS.

Although the EPA has issued a lifetime health advisory recommending PFOA and PFAS levels in drinking water be no more than 70 parts per trillion, the federal agency has yet to set mandatory limits on PFAS in drinking water. It has promised to announce standards for PFOS and PFOA by year's end. But roughly 600 other types of PFAS continue in commercial use without limits.

For most of the five compounds the EPA now proposes to test, "we have a number of publications and likely enough published toxicity data to derive a reference dose and a drinking water guideline," said East Carolina University toxicology professor Jamie DeWitt.

"However, I don't know specifically how many publications or the breadth of toxicity data ... EPA needs to derive a reference dose."

The rule-making process for approving tests and evaluations and, then gathering data and reaching conclusions is expected to take months, if not years. The length of time leads groups such as the Sierra Club to cry foul.

"This work is taking place decades after the fact," said Sonya Lunder, a senior toxic policy adviser at the Sierra Club. "These chemicals are used heavily and without restriction. They are in waxes, shoe polishes, dental floss. PFHxS is in firefighting foam."

Tests by the Centers for Disease Control and Prevention show measurable levels of PFNA and PFHxS in most Americans, Lunder said.

"There are five or more PFAS chemicals measurable in our bodies every day," she said.

Four of the five that the EPA proposes to test were found in the blood of North Carolinians drinking water from the Cape Fear River near a Dupont/Chemours PFAS production plant near Wilmington, DeWitt said.

EPA says the time-consuming testing rigor is necessary to produce reliable results.

Meanwhile, the U.S. House and Senate are hashing out an agreement on PFAS amendments to the National Defense Authorization Act that could restrict use of some of the chemicals or place all of them into Superfund status.

Such a designation would presume them all to be potentially harmful to humans.

Jim Spencer • 202-662-7432