Water samples show high levels of PFAS at the US Pituffik base in Greenland.
Pituffik was the last of the US Air Force’s bases around the world
to have its environmentally harmful firefighting foam replaced.
PFAS Discovery in Greenland:
“The US has long turned a blind eye and said:
There’s a problem, but we don’t care”
Jesper Thobo-Carlsen / Politiken
DENMARK (July 1, 2026) — High levels of toxic chemicals have been found in water samples from the US Pituffik base in northwestern Greenland, which, according to experts, can only stem from decades of use of environmentally harmful firefighting foam.
This is shown by an analysis of data from the US Department of Defense conducted by Politiken.
The Department has published water samples from 2022–2025 on its website, and several of them show levels far exceeding Europe’s limit values for PFAS—so-called “forever chemicals” that hardly break down at all in nature or in the human body.
Lutz Ahrens, a professor of organic environmental chemistry at the Swedish University of Agricultural Sciences in Uppsala, has reviewed the data and explains that the US samples from the base in northwestern Greenland contain four specific types of PFAS that can harm health even in small doses in drinking water.
“We see these four types of PFAS in the water. The levels in Pituffik exceed the values in the guidelines,” he says.
One type of PFAS chemical—PFOS—is particularly toxic and is believed to be carcinogenic. In a water sample from 2022, PFOS was measured at 1,100 nanograms per liter of water. That is about 250 times the EU limit, points out Professor Anders Baun of the Technical University of Denmark, who heads the PFAS Center and has been studying environmentally hazardous substances for more than 30 years.
“There’s no way to explain away the fact that these concentrations are far too high,” he says.
Philippe Grandjean, a professor of environmental medicine at the University of Southern Denmark, reaches the same conclusion.
“That’s many hundreds of times the limit value,” he says.
PFAS (per- and polyfluoroalkyl substances) were discovered by accident in 1938 by a researcher at DuPont, who was developing the Teflon coating used on frying pans. It turned out to be very effective at extinguishing fires, and in the 1970s, the US military began consistently using PFAS-based foam for firefighting at bases and runways around the world. During these regular exercises, large amounts of foam seeped into the ground, and PFAS ended up in the groundwater.
“The release of these chemicals into the environment during training and emergency response operations is a major source of PFAS contamination of groundwater at military bases,” the US Department of Veterans Affairs states on its website.
The high levels of PFOS in Pituffik can only be attributed to the US military’s decades-long practice of conducting firefighting drills using PFAS-containing firefighting foam, according to experts whom Politiken asked to examine the water samples more closely.
“You should never eat your old hat, but this is definitely from firefighting agents,” says Anders Baun.
“Definitely yes,” agrees Lutz Ahrens.
Lutz Ahrens has been sampling PFAS in the environment for more than 20 years. In 2023, he led a project that analyzed PFAS levels on the Norwegian island of Svalbard, which is also home to a military base.
“In Svalbard, we saw levels similar to those in the measurements you sent me—hundreds or even thousands of nanograms per liter of certain PFAS concentrations. So this is a major problem,” he says.
In recent days, Politiken has focused on the legacy left behind by the Americans at the at least 36 bases and military installations they have operated in Greenland over the years. Pituffik Space Base, formerly known as Thule Air Base, is the only one still in operation.
It has repeatedly caused tensions between the US, Greenland, and Denmark. It began in 1953 with the Danish forced relocation of the local population. Later, there have been major concerns about radioactivity, abandoned asbestos, and large quantities of American waste.
The use of PFAS is a completely unexplored chapter.
For decades, the US has used PFAS-containing foam at its bases around the world, but apparently has never formally informed the Greenlandic authorities about its use or the treatment of the water.
Politiken has also found no evidence that the Greenlandic or Danish authorities have consulted the Americans or monitored the water treatment at Pituffik.
We have asked the Danish government whether it is aware of the use of PFAS. The government refers to the Greenlandic self-government, Naalakkersuisut, which has assumed responsibility for environmental oversight in Greenland.
In an email to Politiken, the Greenlandic environmental authorities write:
“The Ministry of Environment, Nature, Energy, and Research is not aware of whether PFAS have been used at Pituffik.”
“Over time and in many countries, PFAS have been used, for example, in firefighting foam. The Ministry therefore also suspects that PFAS may have been used at Pituffik, for example, in firefighting foam,” the statement continues.
Politiken has also asked the US Department of Defense about the US’s use of PFAS in Greenland but has not received a response. However, this use can also be inferred from US documents.
In 2017, the US Department of Defense wrote that nearly all US bases had replaced the toxic PFAS foam—known in English as Aqueous Film-Forming Foam (AFFF)—with the exception of the Pituffik base.
“All Air Force bases except Thule Air Base, Greenland, have received replacement AFFF, and 97 percent of the bases have completed the replacement,” a report to Congress stated.
The following year—in 2018—the US Department of Defense wrote to Congress:
“Due to unique agreements with the host nations, the Air Force will issue two separate contracts for the removal of C8 AFFF at Incirlik Air Base and Thule Air Base; the contracts are expected to be fulfilled by the end of fiscal year 2019.”
Incirlik Air Base is a US Base in Turkey
Anders Baun notes that when the US military wrote that they would remove “C8,” they were referring to PFOS. This highly toxic chemical was used in old firefighting foam.
But that wording—when considered alongside the chemical profile of the samples from Pituffik—may suggest that the Americans initially replaced PFOS with another type of PFAS rather than removing PFAS entirely from the foam, he says.
“They made the elegant substitution of saying, ‘Well, we’re not allowed to use that, but we’ll just use something else that’s similar,’” he explains.
“All the evidence suggests that it’s pretty much just as bad,” he says.
In 2016, the US Air Force funded a phase-out of PFAS-containing foam, but the deadline has been extended. The military subsequently announced a complete ban on PFAS-containing foam starting in October 2025.
Politiken has asked the US Department of Defense when they actually switched to PFAS-free foam in Greenland and why Greenland was last, but has not received a response.
We have also contacted the base’s leadership and the Danish liaison officer at Pituffik, without success.
A source at the Pituffik base, who wishes to remain anonymous, told Politiken that they have been training without foam for the past decade and that the replacement foam arrived a couple of years ago. However, replacement products were available earlier.
Copenhagen Airport replaced its PFAS-containing foam with a PFAS-free alternative as early as 2008, points out Anders Baun. “And they’re still struggling with it in their wastewater. It really is forever,” he says.
Lutz Ahrens, a professor of environmental chemistry, also notes that Sweden and Denmark replaced the PFAS-containing foam a long time ago.
“The US has long turned a blind eye and said, ‘There’s a problem, but we don’t care,’” he says. Experts are divided on whether the many years of PFAS use could pose a pollution risk to Greenland’s natural environment and local population.
The Pituffik base is isolated 120 kilometers southeast of the nearest settlement, Qaanaaq, so there is no threat to their drinking water, and in the ocean, PFAS dilutes rapidly, notes Christian Sonne, a professor of environmental science at Aarhus University.
“As soon as it reaches the marine environment, it becomes so diluted that it has no impact on marine mammals, which travel over long distances,” he says.
“So, of course, it’s unfortunate for the animals and people living at the base and very close by, but I don’t believe it has any significance whatsoever for the Greenlandic environment outside the base—that is, within a radius of 25–50 kilometers,” says Christian Sonne.
PFAS already reach Greenland via air and ocean currents from places such as the United States. A 2023 study of the hunting community in Ittoqqortoormiit in northeastern Greenland, conducted by Christian Sonne and other researchers from Aarhus University, showed that hunters had significantly elevated levels of the synthetic PFAS in their blood. This nearly indestructible substance accumulates in the food chain and is found in the highest concentrations in predators such as polar bears and seals.
“The PFAS we see accumulated in marine food chains stems from long-range transport of pollution over the past 30–40 years,” says Christian Sonne.
Lutz Ahrens notes that any PFAS contamination in the area around Pituffik is in addition to background contamination.
“There is a risk of human exposure. That needs to be investigated. Then there are the animals. PFAS can accumulate in the food chain, and people can eat those animals and be exposed. So this is a huge, huge problem for humans, but there’s also the ecosystem and the animals that live there. We know much less about that,” he says.
Philippe Grandjean also believes it could be a problem if PFAS are released from the base, even if no people live nearby.
“After all, there are animals living there that are part of the human food chain. The thing is, PFAS are virtually non-degradable, which means that all the pollution that escapes will accumulate. And that means this situation will just get worse and worse.”
Anders Baun also sees cause for concern.
“There are some vulnerable ecosystems so far north. We’ve already seen this just from our ordinary industrial use of PFAS down here. If you then directly introduce a source into the Arctic, it won’t get much worse,” he says.
The US water samples are categorized into three groups: “before treatment,” “after treatment,” and “no” treatment. Next to the measurement result of 1,100 nanograms of PFOS, it says “no” treatment.
It is not clear exactly where the samples were taken, or how much water is being treated or left untreated.
The website for the Pituffik base states that “The Department of Defense continues to test, investigate, and identify areas outside the base where there is a known or potential risk of PFAS discharge. The Department of Defense will carry out long-term remediation as needed.”
You have to give the Americans credit for seeming to be able to treat the water effectively, explains Anders Baun.
“They have a lot of experience because they’ve made such a mess of it,” he says. In the samples labeled “post-treatment,” virtually the only substance found is PFBA. “If there are drains from the site leading to a treatment plant, and we then see only that one substance in the effluent, that’s good for the Greenlandic environment,” he says.
But it’s impossible to determine from the test results whether untreated water is also being discharged into the environment, concludes Anders Baun.
Philippe Grandjean points out that the treatment—which typically involves filtration using activated carbon—creates its own problems.
“So what do you do with the filter that’s clogged? Do you just throw it away, or can you incinerate it at over 1,000 degrees to destroy the substances? It’s not exactly a pleasant situation,” he says.
American PFAS manufacturers knew for several decades that the substance was harmful to health but kept it secret until a whistleblower sounded the alarm, explains Philippe Grandjean.
“They’d kept it secret for 50 years, but then it came out around the year 2000,” he says.
Against this backdrop, the researcher believes that the US Department of Defense—which Trump has renamed the “Department of War”—has known since at least 2001 that the substance is harmful, yet has continued to use it for many years. Both in the US and at many of its approximately 750 military bases in at least 80 countries.
“They have huge problems at their bases in Okinawa, Japan, where this has led to truly serious exposure for Japanese residents,” says Philippe Grandjean.
In Okinawa, local residents live close to the bases. The contamination persists for many decades after use, explains Professor Lutz Ahrens.
In March of this year, for example, Japanese authorities in Okinawa measured the highest level of PFAS in a decade in the groundwater near a US base. The concentration was 56 times higher than Japan’s limit, reported the Stars and Stripes. For several years, the US military has denied Japanese authorities access to test the suspected source of the contamination inside the bases.
In Greenland, people are used to not having clear answers.
Kuupik Kleist has been involved in Greenlandic politics for several decades—as a member of the Parliament, party leader of the IA, and head of the Greenlandic government. He has never heard of the Americans’ use of PFAS.
“I don’t know whether they’ve used it or not,” he says, adding dryly:
“As usual.”
