– A former Minnesota attorney general and an executive from 3M Co. faced off Tuesday before a congressional panel examining a product at the center of a national pollution scandal.

For more than half a century, 3M and other chemical companies used per- and polyfluoroalkyl substances, known as PFAS, to waterproof clothes and shoes, make cookware that doesn’t stick and produce firefighting foam that resists high heat. The proliferation of PFAS in the nation’s drinking water, groundwater and soil, as well as U.S. Environmental Protection Agency warnings that PFAS might cause health issues, including high cholesterol, liver problems and cancer, has attracted the scrutiny of Congress.

The House of Representatives is considering dozens of bills meant to limit the use of PFAS, including legislation that would declare all PFAS hazardous and place them in superfund cleanup status.

Lori Swanson, a Democrat who as state attorney general won an $850 million settlement from 3M in a PFAS pollution lawsuit, wants that designation. She told a House subcommittee that Minnesota was “ground zero for the PFAS problem that now confronts the entire country.” Swanson called PFAS “forever chemicals” that don’t break down in nature and are becoming widespread in people and animals, as well as water, soil and food. To illustrate the public health risk, Swanson provided the hearing with a long list of 3M documents that she said showed a pattern of company cover-ups of PFAS toxicity.

“3M knew but concealed information about the dangers of these chemicals for decades,” Swanson testified. She cited one instance where 3M removed a cancer warning from the label of a PFAS product.

In her testimony, Denise Rutherford, a senior vice president at 3M, described an ongoing company commitment to clean up sites where 3M produced PFAS. Rutherford said 3M would properly dispose of firefighting foams containing PFAS. She promised to make 3M a “clearinghouse” of the best research and best practices for cleaning up PFAS and pledged transparency.

But Rutherford insisted repeatedly that PFAS have caused no proven harm to human health and that current public exposure levels have not been unsafe. Her statement included PFOS and PFOA, two types of chemicals that 3M phased out of production.

“In 2000, we voluntarily decided to phase out of PFOS and PFOA production globally,” the company said in a statement to the Star Tribune.

The company said it did so because the chemicals “appeared in unexpected places in the environment and in the general population at levels that were previously undetectable.”

Rutherford’s unequivocal statements drew a frustrated expletive from U.S. Rep. Harley Rouda, D-Calif., chairman of the House Oversight and Reform Subcommittee on Environment, who cited numerous studies and testimony in prior hearings that he said established the dangers of PFAS.

“We’ve had witnesses in here who had devastating illnesses and injuries” because of PFAS,” Rouda told the Star Tribune after the hearing. “For her to sit there and say not a single person has been hurt is disappointing, and I’m choosing my words carefully.”

Republicans on the subcommittee accused their Democratic colleagues of playing politics with the PFAS issue. Ohio Rep. Bob Gibbs said Congress must not “throw the baby out with the bath water,” adding that a lot of PFAS products are beneficial. Gibbs cited an objection by the Advanced Medical Technology Association to widespread regulation of PFAS, which are used in some medical devices.

Rutherford’s insistence that PFAS has not been proven to harm human health had Rep. John Sarbanes, D-Md., citing 3M documents that show the company transferred female employees of childbearing age from working with PFAS in the 1980s because of fears the chemicals might affect pregnancies.

As the hearing ground to an end, Rutherford said 3M disagreed with the effort by many public health experts, scientists and some legislators to designate all chemicals in the PFAS family as hazardous under federal law. That would force PFAS producers like 3M, DuPont and Chemours, which also sent corporate officers to testify, to pay PFAS cleanup costs that could quickly total billions of dollars.

The refusal to agree to a hazardous designation led Rep. Debbie Wasserman Schultz, D-Fla., to criticize 3M for not warning military personnel that PFAS in firefighting foam could build up in humans. With dozens of military bases now beset by PFAS contamination in drinking water, Wasserman-Schultz told the panel of corporate executives, “I don’t know how you sleep at night.”

Few states have studied the problem in detail. Those that have are discovering PFAS in the food chain, water and soil.

The National Wildlife Federation on Tuesday praised the federal effort, which includes PFAS mitigation in a national defense bill passed by the Republican-led Senate. But the federation said that much more needs to be done, particularly at the state level.

“We’ve got solutions. It’s time to use them,” said Oday Salim, a National Wildlife Federation staff attorney.

Salim co-authored a new report that the federation released Tuesday on the Great Lakes region that urges state and federal officials to act aggressively on PFAS. Salim said that state elected officials have the authority, and responsibility, to address PFAS using established federal laws such as the Clean Water Act, Safe Drinking Water Act and other statutes.

Minnesota, among the early states to address PFAS, has set health-based values for PFAS in drinking water, although they are not enforceable limits. The state has also set limits for groundwater and soil, and certain bodies of water including the Mississippi River. Other Great Lakes states such as Ohio, however, have not set standards.

The settlement 3M reached with Minnesota in 2018 provided for the company to give $850 million to the state for water quality programs in the east metro, where 3M for years produced the chemicals. In 2004, traces of the compounds were found in the drinking water of 67,000 people in areas of Lake Elmo, Oakdale, Woodbury and Cottage Grove.

The Wildlife Federation report summarizes recent research showing elevated PFAS levels in great blue herons, bald eagles and tree swallows in the Great Lakes region.

Game, too, can be a path for PFAS exposure in humans. Michigan took the unusual step of issuing a Do Not Eat advisory for deer within 5 miles of a marsh in Oscoda Township, which is near the former Wurtsmith Air Force Base, a site with very high levels of PFAS groundwater contamination.

U.S. Rep. Dan Kildee, the Democrat who represents Oscoda Township, summed up his constituents’ frustration at the hearing.

“3M wants credit for having stopped using PFOA and PFAS, but then it wants us to believe that these chemicals are not dangerous,” Kildee said. “This is ridiculous.”