This story is co-published in partnership with Wisconsin Watch, a nonpartisan, nonprofit investigative news outlet.

Several months ago, longtime Door County commercial fisherman Charlie Henriksen was at a conference with the secretary of Wisconsin’s Department of Natural Resources. The secretary ended the event by asking everyone at the table what keeps them up at night.

“I told him PFAS,” said Henriksen, owner of Henriksen Fisheries. (Disclosure: Henriksen also is a Knock donor.)

PFAS are on the minds of many fishermen and fish eaters these days. Short for per- and polyfluoroalkyl substances and nicknamed “forever chemicals” because of their persistence in the environment, PFAS are a group of thousands of manufactured chemicals that resist water, oil, and heat. Teflon and Scotchguard are among the more famous household products that have used them.

Some common PFAS are associated with health problems including cancer, high cholesterol, and immune, developmental, and reproductive harm, according to the Environmental Protection Agency.

They are also just about everywhere—including in rain, remote lakes and rivers, and every fish the DNR has tested for them in Lake Michigan.

“We consider PFAS ubiquitous,” said Sean Strom, a fish contaminant specialist at the DNR.

As new scientific understandings of PFAS emerge, the EPA is ramping up its control of the chemicals. This March, the agency proposed its first-ever nationwide, legally enforceable limits on PFAS in drinking water, including a reduction in the acceptable level of PFAS consumption through any source by a factor of 200.

The EPA’s proposal has not yet been approved, and local fish testing data from the DNR is still limited. But if regional and state regulators were to follow the EPA’s proposal and adjust their recommendations to the same degree, the DNR’s data suggest that most bay of Green Bay fish would be deemed unsafe to eat.

For Henriksen, the worrisome chemicals represent the latest of many environmental threats he’s faced since he started fishing in the county in the 1970s, including PCB and mercury contamination and invasive mussels that devastate the freshwater food chain. 

“I promote our fish as healthy, and I certainly want them to be as healthy as anything else out there,” he said. “I think they are, but when that worm turns, it’s going to be difficult.”

A study published earlier this year in the peer-reviewed journal “Environmental Research” found high levels of PFAS in wild freshwater fish across the United States compared to the levels in fish sold at grocery stores, including farm-raised and wild-caught ocean fish. The highest levels were in Great Lakes fish. DNR data obtained by Knock showed levels of PFAS in fish from Lake Michigan and the bay of Green Bay that were generally in line with the national study.

The “Environmental Research” study concluded that people who regularly eat freshwater fish may have some of the highest PFAS blood levels of anyone in the country. The study received widespread media coverage and raised fears that fish from lakes and rivers might not be safe to eat.

Henriksen and others in Door County’s fishing industry, concerned about the possible effects of PFAS and ways to regulate them on fishing, counter that there’s not yet enough local data to draw conclusions.

“There needs to be a lot more research before we say, don’t eat fish,” Henriksen said.

Carin Stuth, owner of Baileys Harbor Fish Company, said she shares Henriksen’s concern.

“I think it’s too early for us to generalize a national study on what the fish population is in the Great Lakes or the bay of Green Bay,” said Stuth, whose family has been fishing in the area since the mid 1800s.

She emphasized the importance of water quality, but cautioned that the DNR data is not extensive or nuanced enough to base fishery decisions on.

“We’re still in a fact-finding stage,” she said.

Digging into data

David Andrews, a chemist at the advocacy organization Environmental Working Group, oversaw the “Environmental Research” study. He said the study’s goal was to understand how much freshwater fish may be contributing to PFAS exposure in those who eat it. To do so, he and his coauthors tapped into a trove of EPA data that had not been previously analyzed. The data set included 1,968 fish from streams, rivers, and lakes across the country that the EPA tested for PFAS between 2013 and 2015. More recent data was not available, Andrews said.

“We were surprised by how incredibly high the levels were,” he said. “Even a few servings of freshwater fish could be a major source of exposure to PFOS, in particular, over the course of a year for someone.”

PFOS is a type of PFAS that has been the focus of many studies and regulatory efforts. It is the chemical that the DNR bases its PFAS fish advisories on, and one of two PFAS chemicals that Wisconsin has set drinking water standards for.

Although PFOS production has been phased out in the U.S., the chemical remains widespread in the environment because it does not break down easily. It also is still present in some imported products and is almost impossible to remove once dispersed. (The entire family of PFAS chemicals has not yet been phased out in the U.S., but prominent manufacturer 3M has said it will stop making and using them by 2025.)

Andrews and his coauthors found a median level of 6.6 parts per billion (ppb) of PFOS in fish from US streams and rivers. The median PFOS level in Great Lakes fish was almost double that, at 12.4 ppb. By contrast, the median PFOS level in an FDA study of 66 fish samples available at grocery stores was below detection. Health advisories that the EPA released in June 2022 suggest that virtually no amount of PFAS is safe for consumption. Andrews’s team did not find that fish higher on the food chain accumulated more of the chemicals, as is true for mercury and PCBs.

“What I’ve seen is that the levels are more an indication of the water and food that the fish has been consuming, but not the species,” he said. Research on the topic is ongoing.

EPA data from waters near Door County is sparse. The EPA sampled burbot and walleye off Jacksonport, with levels clocking in at 11.4 ppb and 11.5 ppb of PFOS respectively. The agency also sampled walleye and white sucker at four locations in the bay of Green Bay, with levels ranging from 9.1 to 18 ppb of PFOS.

An emerging picture of PFAS in the bay of Green Bay

Data collected by the DNR is somewhat more detailed. Strom, the DNR fish toxicologist, said the agency has a regular fish contaminant monitoring program that targets mercury, PCBs, and a range of PFAS in the bay of Green Bay and Lake Michigan. Routine testing for PFAS started in 2017.

The agency has so far tested 162 fish in the bay of Green Bay and its tributaries for PFAS, finding PFOS levels from .45 ppb to 122 ppb. The median level was 9.96 ppb. In Lake Michigan and its tributaries, it has tested 55 fish, with PFOS levels from 1.5 ppb to 81.5 ppb. The median level was 16 ppb.

Stuth, the Baileys Harbor Fish Company owner, pointed out that very few of those fish were whitefish, the region’s most important commercial species. The DNR collected just five whitefish in the bay of Green Bay and another six in the lower reaches of the Peshtigo and Menominee Rivers. The agency did not collect any whitefish in Lake Michigan.

“To test five fish?” she said. “That’s really not a good subset.”

Stuth called for a well-planned independent study, sponsored by both Michigan and Wisconsin with input from the fishing sector, to investigate the issue more deeply.

Scientists including University of Wisconsin-Madison chemist Sarah Balgooyen have already begun investigating PFAS in the bay’s water. In January, she and fellow UW-Madison scientist Christina Remucal published a study that used chemical “fingerprinting” to prove for the first time that an underground plume of contamination from the Tyco Fire Products manufacturing and testing facility in Marinette is flowing into the bay. PFAS are the active ingredient in the firefighting foams the company has made at the site since the 1940s. Tyco stopped testing the products outside in 2017, but the plume remains a major source of PFAS pollution, Balgooyen said.

The study didn’t determine how far the groundwater plume reaches or how much of the bay’s contamination it accounts for. Balgooyen said the plume is significant near Marinette, but by the time it reaches Door County, it is likely quite diluted. Little testing has yet been done on the bay’s open water.

Overall, however, Balgooyen said that levels of PFAS in the waters of the bay and Lake Michigan are low. The reason that levels in fish are nevertheless high is that PFAS has a “sticky” chemical structure, she said. Fish and other organisms can’t excrete it, so it builds up in their bodies.

Unfortunately, current technology can’t remove PFAS from the bay and lake. That’s why “the goal of most environmentalists is to stop the source,” Balgooyen said.

Making sense of the numbers

So is it safe to eat fish caught in waters off Door County? One way to answer that question is by referring to fish consumption advisories issued by the DNR. Currently, the DNR has two PFAS advisories for fish caught in the bay of Green Bay and none in Lake Michigan. Rainbow smelt and rock bass caught in the bay should be limited to one meal per week, the agency says.

In Green Bay, most fish consumption advisories are issued for PCBs because of historic pollution from paper mills in the Fox River Valley (a massive cleanup ended in 2020). The DNR’s Strom said that those advisories are typically “more protective than any suggested by the PFAS data.” In other words, if the PCB advisories didn’t exist, there might be more PFAS advisories.

Fish advisories aren’t static, however; they change as scientific understandings of what is safe to eat evolve. The DNR bases its PFAS advisories on guidance from the Great Lakes Consortium for Fish Consumption Advisories, a group of professionals from all Great Lakes states and Ontario. In 2019, that group reviewed the scientific literature on PFOS to come up with suggested limits, which range from unlimited consumption of fish with up to 10 ppb of PFOS to zero consumption of fish with more than 200 ppb of PFOS.

Most Lake Michigan and bay of Green Bay fish the DNR has tested sit comfortably in the unlimited to one-meal-per-week range. The consortium’s report noted that because PFOS doesn’t concentrate in fat, trimming fish before cooking won’t lower exposure. It also noted that for someone who eats fish with PFOS levels warranting an advisory, that fish will likely be their main source of exposure to the chemical. Specifically, the consortium’s report includes calculations that eating one fish meal per month from a body of water with a one-meal-per-month advisory would, on average, account for 93 percent of PFOS exposure.

To calculate its limits, the consortium used a figure from the EPA called a “reference dose.” The reference dose is the amount of a given substance that the EPA believes people can consume every day without experiencing negative health effects over their lifetime.

The consortium issued its recommendations in 2019, based on the EPA’s reference dose for PFOS at the time. But in March of this year, when the EPA proposed its first-ever national drinking water regulations for PFAS, it lowered the reference dose for PFOS by a factor of 200, based on new understandings of how the chemicals affect health.

It’s not clear if or how this change will impact the DNR’s fish advisories. The EPA’s proposed regulation has yet to be approved, and there’s no guarantee the consortium will reflect the new reference dose directly in updated guidance. If the group did make its recommendations stricter by a factor of 200, the DNR’s sampling data suggest that most fish in the bay of Green Bay could fall into the “do not eat” category.

Strom declined to comment on these potential changes but said in an email that the consortium has formed a working group to look into the issue. He noted that the DNR also takes the many health benefits of eating fish into consideration.

“You have to weigh the pluses and minuses of any contaminant with the beneficial aspects of consuming fish,” he said. “That’s the balancing act.”

So far, the pluses win out for Hans Koyen, the general manager of KK Fiske Restaurant on Washington Island. KK’s prides itself on selling fresh fish caught by owner Ken Koyen, Hans’s father and the last commercial fisherman on the island. Hans said PFAS isn’t yet a big concern for him or his father—or their customers.

“Business is great,” he said. If new fish advisories were issued, he said, he would note them on the menu in the interest of transparency but let customers decide what to eat.

As for fishing, he said, “It’s a total way of life for us, and an income that helps sustain the whole community, because it’s one of the very few things that’s totally local.”