Peter Gagnon questions whether his grandchildren should swim in the St. Marys River near Sault Ste. Marie, Ont., because of decades of chemical run-off from the airport.

“That’s what sort of got this started, thinking about grandkids, right? — going in that water and exposing them to harmful chemicals.”

Gagnon and his neighbour, Rick Gartshore, are concerned about contamination from per- and polyfluoroalkyl substances (PFAS) in the city’s Pointe Des Chênes area. 

PFAS are a family of more than 10,000 human-made chemicals that persist in the environment and are highly resistant to heat, water and oil.

Often dubbed “forever chemicals” because of those properties, different types of PFAS are in a range of items, including certain types of makeup, takeout containers, non-stick pans and waterproof clothing.

Health Canada says some animal and human studies show exposure to certain PFAS is associated with reproductive, developmental, endocrine, liver, kidney and immunological effects, among other health issues.

The International Agency for Research on Cancer has classified one particular type of PFAS, perfluorooctanoic acid (PFOA), as possibly carcinogenic to humans.

A problem across Canada

For decades, airports across Canada conducted firefighter training exercises that included the use of foams containing PFAS.

“They’d have a shell of what looked like an airplane, spray it all with gas and light it,” said Gartshore. “Then they would take the firefighting foam … and put it out.”

The PFAS in firefighting foams seeped into the ground. Because the chemicals don’t degrade easily, they accumulated over time and got into the groundwater in communities across Canada.

In North Bay, Ont., PFAS from a firefighter training site at the airport eventually made its way into Trout Lake, the source of the city’s municipal drinking water. 

Tests conducted in 2025 by Ontario’s Ministry of the Environment measured 58 nanograms of PFAS per litre of water in Trout Lake. While the amount is equivalent to only a few drops in an Olympic-sized swimming pool, it exceeds Health Canada drinking water guidelines of 30 nanograms per litre.

The Health Canada guidelines, which cover a total of just 25 specific types of PFAS, are considered an objective to reduce potential health risks related to consuming the chemicals.

Now, the Department of National Defence (DND), which conducted the firefighter training at North Bay’s airport, is investing $120 million to remediate that site and prevent more PFAS from entering the lake.

A proposed class-action lawsuit in North Bay is seeking $100 million in damages related to the loss of property value for homes near the airport because of their proximity to the PFAS contamination.

There are also certified class-action lawsuits launched in Mississippi Mills, Ont., and Torbay, Nfld., that seek damages for diminished property value near areas contaminated with PFAS.

Contamination in the Sault

In Sault Ste. Marie, Transport Canada built a firefighter training area at the southwest portion of the airport property in 1964. Firefighters trained at that site, where firefighting foams that contain PFAS were used, until 1992.

In an email to CBC News, the City of Sault Ste. Marie confirmed that supply wells at the Pointe Des Chênes campground, south of the airport, contained benzene, which was used to light fires at the training site. 

“By the spring of 2008, the benzene concentrations greater than the Ontario Drinking Water Standard [were] detected in both the raw and water samples collected from the water treatment plant on site at Point des Chénes,” it said.

The city continued to monitor water and groundwater samples in the area from 2008 to 2015. In 2015, Ontario’s Ministry of the Environment and Climate Change confirmed with the city that PFAS were also in the well and surrounding groundwater.

Through an access-to-information request, CBC obtained a 3,200-page document from Transport Canada on PFAS monitoring near Sault Ste. Marie’s airport. The package contains 10 environmental monitoring reports from 2011 to 2024.

CBC used artificial intelligence (AI) to analyze the documents and cross-referenced the findings in the documents themselves.

According to a 2011 report by Dillon Consulting Limited, groundwater sampling conducted in January that year at two monitoring wells at the airport exceeded Health Canada’s drinking water guidance values for PFAS at the time.

In 2015, BluMetric Environmental measured PFAS levels “exceeding the applicable site screening values” in groundwater at the Pointe Des Chênes campground south of the airport.

The Sault Ste. Marie Lions Club leased the land from the city and operated the campground from 1985 to 2021. City council decided to close the campground in 2021 due to persistent issues with the water quality, related to benzene and PFAS contamination.

In 2016, Transport Canada installed a granular activated carbon filtration system at the park to treat the well water. It proved successful at filtering benzene, but reports at the time found it did not effectively reduce PFAS concentrations.

Six years later, Transport Canada also equipped the park with an advanced auxiliary water treatment system, which proved effective at reducing PFAS to below laboratory detection limits in the treated water.

The city is now looking for new tenants to lease the property as the well water is considered safe to consume.

Private wells affected

In addition to the former Pointe Des Chênes campground, several residential homes near the airport draw their water from private wells that were contaminated with PFAS.

According to the documents obtained by CBC, a firm called Arcadis Canada tested 28 private wells for PFAS in 2023. Seven of those homes had detectable PFAS levels and one home had concentrations of 255 nanograms per litre, greatly exceeding Health Canada’s drinking water guidelines of 30 nanograms per litre.

In 2024, Arcadis continued its testing program and collected raw water samples from nine private wells. PFAS were detected at seven of them. At one home, concentrations reached 460 nanograms per litre for the sum total of 25 types of PFAS.

Another home had concentrations of 33 nanograms per litre. The remaining properties had concentrations below the Health Canada guidelines.

Transport Canada redacted the addresses of the affected properties in the documents to protect to homeowners’ privacy. Therefore, CBC cannot confirm if the same seven properties tested positive for PFAS both years. The federal department has since installed PFAS filtration systems at the homes where levels exceeded Health Canada’s drinking water guidelines.

City not concerned

In an email to CBC News, City of Sault Ste. Marie spokesperson Tessa Vecchio said the city has no concerns about the safety of the municipal drinking water system “as the issue is specific to groundwater in the affected airport vicinity.”

Sault Ste. Marie draws its municipal drinking water from Lake Superior, around eight kilometres northwest of the airport, and six deep wells. 

For Gagnon and Gartshore, contamination at the airport is part of a bigger problem.

“You have a localized problem over there, you have a potential problem for the area and you have a worldwide problem going on,” Gartshore said.

PFAS are bio-accumulative, which means the chemicals build up in the tissues of living organisms over time.

Exposure to PFAS from local sources — the airports are an example — is on top of exposure from everyday products like non-stick pans and fast food packaging. 

“Our children, our grandchildren are going to be dealing with this because throughout the whole world, it’s just accumulating, accumulating, accumulating,” Gartshore said.