(Bloomberg) -- Carbonated waters from LaCroix, Topo Chico, Poland Spring and Perrier all have levels of per- and polyfluoroalkyl chemicals, called PFAS, that are slightly higher than what some scientists deem safe, according to a report from Consumer Reports.

While none of the brands exceeded the suggested levels for PFAS in tap water published by the U.S. Environmental Protection Agency, that limit is seen by many scientists and some state regulators as too lax. The beverage industry’s trade group and several of the manufacturers called the testing flawed and said their products are safe.

The report from the nonprofit consumer watchdog also found that Deer Park, a popular brand of still water sold by Nestle SA, has higher levels of PFAS. Unlike fizzy water, most non-carbonated water didn’t exceed the threshold of 1 part per trillion, according to Consumer Reports.

“I was surprised that so many of the carbonated bottled waters contain PFAS,” Brian Ronholm, director of food policy for Consumer Reports, said in a phone interview. At the same time, “there’s a good story overall for non-carbonated water, in that virtually all of the brands tested below our recommended level.”

Ronholm said it wasn’t clear whether the chemicals’ concentrations had somehow been increased through carbonation, or if some brands hadn’t filtered the chemicals out of the source water that they used.

Topo Chico, owned by Coca-Cola Co., had the worst score of carbonated waters, with 9.76 parts per trillion. Most brands tested were only slightly above 1 part per trillion, with Poland Spring at 1.66, Canada Dry at 1.24, LaCroix at 1.16 and Perrier at 1.1. For non-carbonated water, Deer Park tested at 1.21 parts per trillion.

Industry Responses

The International Bottled Water Association has set a PFAS standard of 5 parts per trillion for its members. The trade group, known as IBWA, said in an email that the Consumer Reports testing is “misleading” and “not based on sound science.”

National Beverage Corp., the maker of LaCroix, also disputed the testing methods and said its products are “subject to strict quality control and robust filtration systems.” The company said the samples tested exceeded “the most stringent PFAS requirements” in the U.S.

Coca-Cola said its products tested below drinking water limits for PFAS and meet other regulatory criteria. The company said it continues to “make improvements to prepare for more stringent standards in the future.”

Nestle, the maker of Deer Park, Poland Spring and Perrier, said it’s “committed to providing consumers with the safest and highest quality bottled water products” and that its latest published tests “indicate undetectable levels of PFAS” for the brands named by Consumer Reports.

Nestle also said it has worked with IBWA to encourage the U.S. Food and Drug Administration to boost regulation related to the chemicals’ content in bottled water. Standards from the FDA would “help avoid a patchwork approach to testing and reporting related to PFAS,” the company said in an email to Bloomberg.

Keurig Dr Pepper Inc., the owner of Canada Dry, said it adheres to the EPA and state water requirements for its products and “our test results are well below the strictest state regulations for PFAS levels.”

“The health and safety of our consumers is a top priority, and we stand behind the quality of our products,” the company said in an email.

Pervasive Chemicals

PFAS, used in hundreds of products that are slippery, non-stick or stain-resistant, have been made for decades by industrial giants like 3M Corp. and Dupont. That company since separated the business into Chemours Co., but it is still named in many lawsuits.

The chemicals are pervasive in U.S. drinking water, and don’t degrade naturally, earning them the “forever chemical” moniker. They have been linked in studies to health problems like cancer and poor immune health.

While the EPA has issued guidance that levels should be below 70 parts per trillion, many states have set their own limits lower, and scientists have said 1 part per trillion is a level that would protect human health in drinking water, given exposure from multiple sources like household products and food. Meanwhile, studies, lawsuits and regulatory evaluations are ongoing.

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