As the City of Thornton’s water treatment plants have found themselves at times outmatched by the task of stripping PFAS, or per- and polyfluoroalkyl substances, from drinking water, the city has undertaken some of its own investigations to determine the sources for that contamination. Yes, says Martin Kimmes, water treatment and quality manager for the City of Thornton, there’s PFAS from Suncor, a petroleum refinery, running into Sand Creek, but that’s downstream from where Thornton draws water. Yet elevated PFAS levels also appeared at every municipal wastewater treatment plant upstream of the city — those treatment plants don’t put PFAS in the water, rather the chemicals enter the wastewater stream from homes and businesses.
“It’s just in so many different products — we’re washing it off our bodies into the showers, we’re washing our clothes and everything has [durable water] repellent on it these days,” Kimmes said. “We have to get PFAS out of consumer products before we’re going to see it decline in our water.”
PFAS, a family of chemicals linked to serious health issues ranging from certain types of cancer to developmental and reproductive effects, taint drinking water supplies around the world, including in more than two dozen Colorado communities. These “forever” chemicals break down very slowly, perpetually posing concerns for people and wildlife.
PFAS has leaked into Colorado’s groundwater and waterways from use around industrial businesses, military bases, airports and landfills. But the chemicals are also found in water-repellant and grease-proofing treatments used for clothing, carpet, upholstery, non-stick cookware and food packaging. PFAS has been commercially produced since the 1940s but its toxicity wasn’t publicized until the late 1990s, and regulations to protect public health are only now coming online.
Colorado is taking strides to address PFAS on multiple fronts, limiting certain consumer products known to be laden with the chemicals. And also, in a rare step, the state is looking at industrial sources of contamination and asking polluters to cut back and clean up. Plus, with new federal regulations, adopted in April 2024, water providers, including Thornton, must take action to reduce PFAS levels in drinking water by 2029.
Colorado’s House Bill 1345, passed in 2022, restricts the sale of certain products that contain intentionally added PFAS, including carpets, cosmetics, fabric treatments, food packaging, and furniture. The bill takes a phased approach — cookware restrictions began in January 2024 and additional restrictions will come online in 2025 and 2027. The bill banned the most products of any PFAS bill to date in the U.S., according to Safer States, an alliance of environmental health organizations. That bill also included a first-in-the-nation prohibition on the use of PFAS to extract oil and gas. The measures aim to protect consumers from exposure, and to reduce sources of PFAS contamination.
While major water contamination in Colorado from PFAS has been traced to the use of firefighting foam, industrial sources of PFAS include sites that manufacture paint and coating, plastics, or electronics; process petroleum; or fabricate metal.
Suncor, the state’s only major petroleum refinery, sits along Sand Creek in Commerce City, just north of Denver. The Colorado Department of Public Health and Environment (CDPHE) has found PFAS levels in the water discharged from Suncor as high as 2,500 parts per trillion (ppt). Suncor attributes the PFAS in nearby groundwater to firefighting foams historically used at the refinery, and the company says it is working with CDPHE to test surrounding groundwater and streams. It has also stopped using firefighting foam that contains PFAS, and will try to contain all foam used in the event of an emergency. When CDPHE renewed Suncor’s discharge permit in March, it set limits on how much PFAS the facility can release into nearby waters for the first time — restricting its PFAS discharge to 70 ppt.
“We’re really focused on making sure that we’re not continuing to add to the problem, so cutting off any additional contributions to PFAS getting out into the environment, and then where it is, really working on addressing that on a case-by-case basis,” says Trisha Oeth, CDPHE’s environmental health and protection director.
In contrast, most wastewater treatment plants with permits to discharge water to a stream do not yet operate under a PFAS limit but instead must monitor for PFAS and investigate the sources of PFAS that feed into their treatment facilities.
Environmental groups have appealed the Suncor permit.
“It doesn’t really require Suncor to clean up its act far enough or fast enough,” says Michael Freeman, an attorney with Earthjustice.
The appeal raises concerns that Suncor’s discharge permit relies on an outdated PFAS limit of 70 ppt from a 2016 U.S. Environmental Protection Agency (EPA) health advisory level for drinking water. The permit also gives Suncor more than six years to comply. And while the facility’s limits will be set on a daily maximum, the state only required water testing once a week. Earthjustice hired a hydrologist to monitor PFAS levels upstream and downstream of Suncor, and that data suggests Suncor is responsible for 18% to 27% of the PFAS in Sand Creek.
“We’re glad they’re adding PFAS limits for the first time to Suncor’s permit, but they’re doing so in a way that’s not strong enough to protect local communities and people’s drinking water and public health,” Freeman says.
Suncor also contested the permit, saying the treatment will be expensive, take time to construct, and offer limited gains. Research commissioned by Suncor counters that non-refinery sources comprise 89% of the PFAS. In correspondence, company staff contend that contamination in Sand Creek “reflects the widespread historic use of PFAS by companies and individuals at large — and is not a Suncor specific issue.” In their tests, PFAS concentrations were routinely above 70 ppt upstream of Suncor.
In April 2024, the EPA established new drinking water standards for five PFAS and some combinations of the thousands of PFAS variants. The goal is to see levels at zero, but the enforceable levels for PFOS and PFOA are set at 4 ppt. Up to 10% of public drinking water systems may need upgrades to comply with new rules, and nearly $1 billion in federal money through the Bipartisan Infrastructure Law will fund testing and new treatment facilities at public water systems.
To consistently meet this new standard, Thornton will need to build a new $40 million to $150 million treatment plant, Kimmes says. The city is still exploring whether it will pursue federal support.
Though the EPA has worked on setting industry limits, the process will take years. States can address PFAS sources more quickly.
“Colorado is actually a leading state in terms of thinking about PFAS discharge from industry into waterways, water systems, and wastewater,” says Sonya Lunder, director of community science for the Natural Resources Defense Council. The state efficiently set standards, and required wastewater testing and source identification, Lunder says, but if this is what leading looks like, that’s “bonkers.”
“It’s happening in reverse order,” Lunder says. “It’s kind of wild to think about the really intense and ambitious goals for drinking water, and they’re happening well in advance of any conversation about prevention.” H
Independent journalist Elizabeth Miller has written about environmental issues around the American West for publications including The Washington Post, Scientific American, Outside, Backpacker and The Drake.
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