US EPA to investigate tire preservative linked to toxic runoff and salmon deaths

Federal environmental regulators are taking action that eventually could transform the way motor vehicle tires are manufactured to reduce toxic runoff from a substance used in tire production that kills or harms some fish, including federally protected coho salmon and steelhead trout.

In doing so, the Environmental Protection Agency is granting a petition submitted by three West Coast tribes, including the Yurok in Northern California, seeking action under the nation’s landmark toxic substances law to address the threat posed by a chemical contained in most or all tires to salmon stocks at the center of tribal culture.

It’s also following the California Department of Toxic Substances Control and the Washington State Department of Ecology into the regulatory fray over a substance that has caused increasing alarm since its discovery in waterways around Puget Sound a few years ago.

“This is a significant victory. It is a significant first step,” said Elizabeth Forsyth, lead attorney for Earthjustice, a nonprofit that works with the tribes.

But how far the federal agency will go remains in question. A representative said it could not “commit to a specific outcome or timeline.”

It’s also unclear if it can act quickly enough to make a difference, given the lethality of the chemical and the time needed to fully understand its varied impacts and find satisfactory substitutes.

“We think it’s a decade or more that it’s going to take,” said Nat Scholz, ecotoxicology program manager for the National Oceanic and Atmospheric Administration’s Northwest Fisheries Science Center, who has been investigating salmon die-offs around Seattle for more than two decades.

“This is a real extinction risk on a decadal timeline,” Scholz said.

At issue is a rubber preservative called 6PPD — an abbreviation for a much longer chemical name — used for 60-plus years to prevent automobile tires from cracking, crumbling and breaking down prematurely due to wear, tear, temperature fluctuations and exposure to ground level ozone and oxygen.

But a landmark study published in 2020, and associated research since then, shows that 6PPD actually reacts with ozone to create something called 6PPD-quinone, which leaches out of tire dust and particles deposited on roadways. The chemical then washes into streams and other waterways when it rains, especially during a season’s “first flush,” or even in snowmelt.

The findings resulted from long-running inquiries into why so many Pacific Northwest coho salmon were dying each year during their fall migration into freshwater streams near the Puget Sound — a phenomenon known as “urban runoff mortality syndrome.”

Scientists at the San Francisco Estuary Institute, who partnered in the research, also found fatal levels of 6PPD-quinone in four Bay Area streams, raising concerns about watersheds where diminished coho populations still exist, like the Eel and Klamath rivers.

In their petition granted last week, the Yurok, Port Gamble S’Klallam and Puyallup tribes formally asked the EPA to prohibit the use of 6PPD in tire production. Many others alarmed by the ubiquity of the product resulting from ozone exposure support the move, including the attorneys general of Washington, Oregon, Vermont and Rhode Island.

AttorneysGeneral6ppd.pdf

The Institute for Fisheries Resources and Pacific Coast Federation of Fishermen’s Associations, working with nonprofit Earthjustice, also have put tire manufacturers on notice that they plan to sue for illegal harm to species listed under the Endangered Species Act.

60-day-notice-re-6ppd-in-tires.pdf

The EPA has agreed only to launch rule-making proceedings, including in-depth risk analysis and investigation of potential alternatives to a substance the U.S. Tire Manufacturing Association claims is essential to driver and passenger safety.

“This is going to be a step-by-step process,” said Tom Groeneveld, senior adviser in the EPA’s Existing Chemicals Risk Management Division. “We’re using rules to collect information, but we cannot commit to any step that would be, like, a regulatory prohibition down the line.”

But Groeneveld acknowledged the “extreme toxicity” posed by 6PPD-quinone for certain fish and said the EPA already has been involved for years with an interstate working group reviewing evolving science on the topic.

He also said the agency is developing rules for manufacturers who use 6PPD in their products to submit unpublished health and safety studies, separate from the petition granted last week.

He said, however, that the EPA was not prepared to issue an immediate edict on the substance but wanted to collect more information.

There’s lots more scrutiny coming on the issue, too. The 2020 study set off a flurry of additional investigation and consultation around the globe, with scientists in places like Australia, Japan, the United Kingdom and China also finding 6PPD-quinone, not only in streams but, in China, human urine, especially that of pregnant women, experts said.

Researchers have found that endangered coho salmon — now present at a mere fraction of historical population densities — are most sensitive to the compound, dying rapidly after exposure following brief periods of disorientation, circling and gasping. Other species in the salmonidae family, including Chinook salmon, steelhead trout and brook trout, also are reactive, though exposure may not result in death.

Meanwhile, still other related species, like white sturgeon and Arctic char, seem to tolerate exposure, according to a study published last year.

“It’s a very interesting-slash-alarming finding,” said Rebecca Sutton, a senior scientist at the San Francisco Estuary Institute who has been working on the issue.

The full scope of the impact on fish and other aquatic species is still under investigation, and any human health impacts remain unknown, though the fact that scrap tires are used in playground surfacing, walkways, paths, bike trails and synthetic turf on athletic fields makes such research all the more important.

The U.S. Tire Manufacturers Association says it has been working with regulators and scientists to resolve questions around 6PPD and seek solutions, but at the same time has not identified an alternative to preserve tire integrity and, thus, keep motorists safe.

USTMA Media Statement_11.3.23.pdf

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The California Department of Toxic Substances Control, as of Oct. 1, is requiring manufacturers with tire sales in California to notify the agency if their products contain 6PPD. The deadline is Nov. 30.

By March 29, companies confirming the chemical use must inform the state agency that they no longer will use it or will quit selling tires in California, or are analyzing potential alternatives for performance and evidence they don’t come with their own unintended consequences.

Even if new tire formulations are eventually developed, millions of vehicles would still be driven for some time before their tires were changed, Scholz and other experts point out. Millions more worn, used tires are stashed around the country and at risk of continued chemical leaching, meaning some other action would be needed to keep contaminated runoff out of waterways, including stormwater capture and natural filtration ponds as part of infrastructure development and maintenance.

“There’s no one size fits all,” Scholz said.

You can reach Staff Writer Mary Callahan (she/her) at 707-521-5249 or mary.callahan@pressdemocrat.com. On X/Twitter @MaryCallahanB.