Milk from a Central Maine dairy farm contained levels of a harmful “forever chemical” that were 60 to 150 times higher than health standards, triggering a state investigation and raising new concerns about PFAS contamination on farms.

The levels of contamination in the farm’s milk are the highest, by far, documented in Maine for an agricultural setting and, at 32,200 parts per trillion, potentially the highest ever recorded in milk in the country.

In fact, samples collected from the unnamed farm had 23 times as much PFAS – industrial compounds linked to cancer and other health problems – as were found at a York County dairy that drew national attention to the issue of potentially contaminated milk.

“They were very startling and very concerning for this individual farm, and certainly not something that we were expecting,” said Nancy McBrady, director of the Maine Department of Agriculture, Conservation and Forestry’s Bureau of Agriculture, Food and Rural Resources.

Though McBrady and other officials with the department were alarmed by the unprecedented levels, they said consumers were not at risk from the contaminated milk because it was diluted when it was mixed with milk from other farms at the processing plant. The department also said the discovery shows that the state’s periodic testing and supplier-tracing system works.

The department said the farm has stopped selling milk and beef, but it did not identify the farm or the processor in a public statement about the contamination. The Press Herald asked for the name of the farm and processor, but the department said it would not release the information before next week.


“We require time to first properly notify the entities involved,” a department official, Shannon Ayotte, said in an email.

Though Maine’s public records law does not require notification of “entities involved” before public records are released, it also doesn’t require the state to release the information immediately, only that an agency or official makes a good faith effort to respond to a request within an estimated time frame.

Investigators from the agency as well as the Department of Environmental Protection are looking for sources of the contamination, potentially including sludge used as fertilizer or firefighting foam laced with chemicals.

“Our testing approach allows us to identify and investigate potential issues of concern before they can become a problem, so we can ensure that retail milk in Maine is safe,” Amanda Beal, Maine’s agriculture commissioner, said in a statement on Friday. “At the same time, the state is committed to helping farmers who may be impacted by PFAS contamination to find a viable path forward to continue farming and producing products that are safe for people to consume.”

However, the discovery is likely to increase pressure on the state to conduct more widespread testing of farms and agricultural products. Health and environmental groups have been pushing for such testing since high levels of PFAS were found on the Arundel farm of Fred Stone and were linked to sludge spread on his farm fields.

“It’s very, very troubling,” said Patrick MacRoy, deputy director of the Environmental Health Strategy Center, a Maine-based nonprofit active on PFAS issues. “It clearly illustrates what we have been saying all along: this problem extends far beyond Fred Stone, and it is incumbent on the state to test all of the farms and the products that have been exposed to sludge.”



Maine’s agriculture department was alerted to a potential problem while testing retail milk samples for PFAS, following up on similar testing conducted in the spring of 2019 that found no issues with milk.

While 19 of the 20 latest samples were below the reporting limit, one was high enough to prompt follow-up inquiries with the unidentified milk processor, which in turn led to tests of raw milk from several supplier farms.

Tests in June and July revealed levels of the chemical perfluorooctanesulfonic acid, or PFOS, that ranged from 12,700 to 32,200 parts per trillion at the central Maine farm. That higher figure is 153 times above the 210 parts per trillion cutoff for when milk can no longer be sold commercially in Maine.

McBrady said the farm was a small operation with 40 to 50 milking cows, meaning its contribution to the overall milk supply was also small.

“Retail milk, we feel based on this testing, continues to be a safe product in Maine,” McBrady said in an interview. “Retail milk is a product of multiple producers that are blended together and are testing out very well.”


PFOS is one specific variety within the broader PFAS family of chemicals that have been used for decades in products found throughout modern society.

They create non-stick surfaces in cookware, help carpets and clothing repel grease or water, and allow airport or military firefighters to extinguish infernos created by burning fuel. These per- and polyfluoroalkyl substances, or PFAS, also coat some types of dental floss, microwave popcorn bags and medical equipment.

While manufacturers assert that newer varieties of PFAS are safe, the chemicals are coming under increasing health scrutiny.

The strong chemical bonds that have made PFAS so popular with manufacturers (and convenience-obsessed consumers) also mean they do not break down easily in the environment or the body. Some PFAS linger for indeterminate amounts of time, hence the nickname “forever chemicals.”

One of the oldest and best-studied types, PFOS has been linked to cancer, low birth weight in infants, high cholesterol, immune suppression and changes to fertility and reproductivity. As a result, the U.S. Environmental Protection Agency set a drinking water “advisory level” of 70 parts per trillion.

Manufacturers in the U.S. voluntarily phased out the production of PFOS and a related chemical, PFOA, by 2002. But the chemical was so widely used that, between 1999 and 2012, PFOS was found in 99 percent of sampled blood from U.S. residents. PFOS and its PFAS cousins also routinely show up in human waste and, in turn, in the sludge used as fertilizer in Maine and across the country.



Sludge appears to have been the contamination source at Stoneridge Farm, the Arundel dairy run by the Stone family. Over a period of decades, farmer Fred Stone spread treated sludge, or “biosolids,” from local waste treatment plants – as well as some waste from a paper mill – on his and other farms in order to enhance the nutrient levels of his fields.

In 2016, the Kennebunk, Kennebunkport and Wells Water District found elevated levels of PFAS in a well on Stone’s property. Subsequent testing by the Maine Department of Environmental Protection and Department of Agriculture, Conservation and Forestry found levels of PFOS at 1,420 parts per trillion.

Stone said the contamination – which he blames on state policies that actively encouraged the reuse of sludge as fertilizer – has ruined his family’s century-old farm and is potentially affecting his and his wife’s health. He lost his contract with a processor, has been unable to sell milk and has to kill of more than half of his herd.

Stone sued several PFAS manufacturers, the Kennebunk and Ogunquit sewer districts, as well as a paper company. He has also been actively pushing for regulatory changes in Augusta and Washington, D.C., even as he fights with the U.S. Department of Agriculture for more than a year’s worth of dairy disaster relief payments he contends he is owed.

“The toxic chemicals that I never used and had never even known about until two years ago contaminated my cows – which I really take exception to – and ruined my farming operation and hurt my family,” Stone said in March 2019 during a news conference on his farm. “I want the state of Maine to make sure that no other farming families have to go through what’s happening to us. Believe me, I would not wish this on my worst enemies.”



The Stoneridge Farm situation already has had ramifications in Maine and – along with a larger dairy farm contamination case in New Mexico – led to nationwide conversations in the dairy industry about PFAS.

In early-2019, the administration of Gov. Janet Mills began requiring all wastewater treatment plants to begin testing for PFAS before distributing treated sludge for land application. The DEP has also imposed some restrictions on its use when PFAS is present at elevated levels, although environmental and health groups contend the state’s policies are still too lax to protect public health.

Earlier this year, a PFAS Task Force created by Mills produced a report after months of meetings. Among the report’s recommendations are “greatly expanded testing of agricultural produce and products” grown in soils fertilized with sludge and continued restrictions on land application of biosolids.

The task force also called on Maine to require manufacturers to disclose use of PFAS in products and require safer alternatives when they are available.

But MacRoy, with the Environmental Health Strategy Center, said the state should have begun testing milk on farms where sludge was spread as soon as Stone’s case became known more than three years ago. He called the state’s 210 parts per trillion action-level for milk was “an order of magnitude too high” to protect public health and said testing batches of retail milk every few months misses potential PFAS hotspots around the state.


“I think this deserves more rapid attention than that and deserves actual testing of milk on the farm level,” MacRoy said.

But McBrady, with the state agriculture department, said it is dangerous to paint all farms that used sludge with a broad brush because state testing has shown many do not have PFAS contamination issues. She also defended the state’s periodic retail milk testing plan.

“I think we have pretty precise way to go forward to find and ferret out areas of concern,” McBrady said. “And we can point to this example as doing exactly that.”


CORRECTION: This story was updated at 6:05 p.m. on July 29, 2020, to correct the defendants in Fred Stone’s lawsuit. 

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