Three tribes petition EPA to ban tires with 6ppd

The non-profit Earthjustice has filed a petition with the U.S. EPA demanding an immediate ban on the manufacture and sale of tires containing 6ppd. The antidegradant is crucial to consumer safety, but it can morph into 6ppd-quinone during tire abrasion, an offshoot that is toxic coho salmon (pictured) and other fish critical to the livelihood of Native American tribes in the Pacific Northwest.

WASHINGTON, D.C.—On behalf of a coalition of three American Indian tribes in the Pacific Northwest, the non-profit Earthjustice has filed a petition with the U.S. EPA demanding an immediate ban on the manufacture and sale of tires containing 6ppd.

The 17-page petition, filed Aug. 1 on behalf of the Puyallup (Tacoma, Wash.), Yurok (Northern California) and Port Gamble S'Klallam (Kitsap Peninsula, Wash.) tribes, states that water contamination in the rivers, streams and soil of the expansive region is "imperiling salmon recovery" and may present a danger to the members of the tribes themselves.

"To see 6ppd-quinone kill the salmon that are reared in the Port Gamble S'Klallam Tribe's own streams and from its own hatchery is an unconscionable slap in the face to a people who rely on salmon for their well-being," said Josh Carter, Port Gamble S'Klallam Tribe's environmental scientist.

Carter said this is "in addition to being a gross violation of the tribe's rights as enshrined in the 1855 Treaty of Point No Point," a treaty on which the federally recognized Port Gamble S'Klallam Tribe is an original signatory.

"If EPA truly cares about protecting the environment and the tribe's treaty rights, not just industry's pocketbooks, it will act now," he said.

The petition asks that regulations be established "prohibiting the manufacturing, processing, use and distribution of 6ppd in and for tires" and cites the EPA's own Toxic Substances Control Act as a regulatory threshold.

TSCA mandates that the EPA ban or regulate "chemicals in commerce that pose unreasonable risks to human health or the environment" and gives the agency authority to order phaseouts of existing chemicals on the "fastest practicable timeline."

The regulations the tribes are seeking essentially would require tire companies to offer tires that are free from 6ppd—a similar outcome also being sought by the U.S. Tire Manufacturers Association and the California Department of Toxic Substances Control.

The antidegradant 6ppd is crucial to consumer safety in preventing cracking and splitting of tires during tire wear. However, 6ppd can morph into 6ppd-quinone during tire abrasion (reacting with ground-level ozone), an offshoot that is toxic to fish—and not just coho salmon, according to Earthjustice.

According to the coalition's petition, rainbow trout, steelhead trout, Chinook salmon, brook trout, white spotted char and "likely other species that have not yet been studied" are being affected.

6ppd has even been found in stream-side plants and mushrooms, according to the petition.

More than any other species, salmon and steelhead—key to the cultures and overall ecosystems of the region—have declined (via fish ladder counts) "drastically" and are listed as either endangered or threatened in many cases under the Endangered Species Act.

While academic studies have placed the mortality rate in coho salmon—provided by the Puyallup Tribe for the laboratory studies—that come into contact with 6ppd-quinone at 50 percent, the tribes put it closer to 100 percent.

"Exposure to 6ppd-quinone can kill coho salmon within hours, and the chemical is responsible for urban runoff mortality syndrome, which kills up to 100 percent of coho returning to spawn in urban streams," the Aug. 1 petition states. "The tribes contend that 6ppd in tires poses unreasonable risks to the environment, requiring the EPA to regulate the chemical under the Toxic Substances Control Act."

The chemical is not only present in stormwater runoff and urban watersheds, but also in sediments and soils, household dust, and human urine (especially that of pregnant women). Emerging science has pointed to toxicity in mammals, indicating a potential risk to human health.

The petition goes on to say that while salmon and steelhead trout are "keystone species" for humans, at least 135 other species depend on salmon and steelhead for food, including orca whales, eagles, bears, wolves and seals.

Salmon stocks also support an estimated 16,000 jobs in the commercial and recreational fishing industry, according to Earthjustice.

The non-profit calls 6ppd-quinone "the second most toxic chemical to aquatic species ever evaluated by the EPA."

The first is the chemical war agent parathion, according to the petition, which has been banned in the U.S.

"It is time for the EPA to phase out this highly toxic chemical that is killing salmon," said Elizabeth Forsyth, senior attorney with Earthjustice's Biodiversity Defense Program. "Tire companies have known for years that they need to move beyond 6ppd to find viable alternatives. EPA action is urgently needed to spur that change.

"The extreme toxicity of this little-known chemical should be alarming to anyone who cares about our planet's biodiversity and waterways."

The EPA has 90 days to respond to the petition, an Earthjustice spokesperson told Rubber News.

EPA did not respond to requests for comment for this story.

Thus far, the public has heard from the U.S. EPA, the U.S. Tire Manufacturers Association, the California Department of Toxic Substances Control and from companies involved in the search for an alternative for 6ppd.

With the legal document filed Aug. 1 with the EPA, the three tribes whose livelihoods depend on the aquatic species officially have joined the conversation.

The effort to find an alternative to 6ppd already is underway, with the USTMA compiling a consortium of 16 of the world's largest tire manufacturers to tackle the research; and the California Department of Toxic Substance Control outlining the process for the USTMA.

The companies—which include Michelin, Bridgestone, Goodyear and Continental, among others—will be guided in their research by California's Safer Consumer Product Regulations, and the listing of 6ppd as a "priority product" within the program.

The SCPR framework helps products and chemicals comply with Federal Motor Vehicle Safety Standards and other consumer, vehicle and tire manufacturer requirements.

The DTSC on July 26 officially adopted a rule that requires manufacturers of tires (domestic or foreign) for sale in California to evaluate safer alternatives to 6ppd, an additive that helps reduce tire cracking and wear.

Elastomer companies like Flexsys America L.P. have thrown their own research and development hats into the ring to assist with the alternative research.

The new California rule applies to any tire in "the stream of commerce" in the state and takes effect Oct. 1.

Domestic and foreign manufacturers have until Nov. 30 to notify DTSC if they manufacture 6ppd-containing tires that are used in California, a DTSC spokesman told Rubber News.

According to the USTMA, any potential alternative to 6ppd "must provide equivalent tire safety and performance to 6ppd, while improving environmental metrics."

The USTMA believes a full mitigation strategy also must be undertaken, one that includes infrastructure efforts to filter or eliminate tire road wear particles, which contain roughly 50 percent tire abrasion particles and 50 percent road-related particles.

To this end, progress has been made.

The Recycled Rubber Coalition, based in Washington D.C., said new research demonstrates that rubber-modified asphalt, a major use for ground rubber from recycled tires, "is a safe and smart solution" to the 6ppd-quinone problem.

A study at the University of Nevada recently confirmed that rubber in asphalt mixtures can help absorb and retain 6ppd-quinone released by tires on the road, according to the RRC.

"The Recycled Rubber Coalition has long supported the use of recycled rubber from scrap tires in rubber-modified asphalt, which doubles the lifespans of roads, produces less CO2 and keeps scrap tires out of landfills," Stratton Kirton, a spokesperson for the RRC, told Rubber News. "We're excited by the new study from researchers at the University of Nevada confirming that the use of recycled tire rubber in asphalt mixtures can help absorb and retain the 6ppd-quinone released by tires on the road, ultimately lowering the levels of this chemical in the environment."

According to a study completed in 2021 at the University of Washington (Tian et al.), 6ppd reacts with ozone (O3) in the ambient air to form 6ppd-quinone, which kills coho salmon as they migrate upstream to spawn in the waterways of the Pacific Northwest.

The two-year-old Tian et al. study is the root motivation for the process today that has 6ppd in the crosshairs of the California EPA, which oversees the DTSC.

The toxic chemical—6ppd-quinone—has been fatal to about half of the coho salmon studied in the laboratory.

The juvenile salmon were offered for the studies by the Puyallups, who have lived along the shores of Puget Sound for thousands of years.

"Since time immemorial, the Puyallup Tribe has fished and protected the water that flows through our homelands," the governing body for the Puyallup Tribe said in a statement to Rubber News. "We have witnessed first-hand the devastation to the salmon species we have always relied upon to nourish our people. We have watched as the species have declined to the point of almost certain extinction if nothing is done to protect them.

"We have suffered years of reduced fishing, now only seeing hours of fishing where there used to be months of fishing. The discovery that 6ppd(-quinone) is killing the fish in these waters could be exactly what saves salmon for us and all of the country.

"That is why we have joined this petition to act upon the knowledge we now have, to save and protect our fish and other species impacted by this toxic chemical. We will always act to protect the fish, the water and our lands."

As the largest Native American nation in California, the Yurok Tribe has approximately 6,400 members living on the Yurok Reservation and within the adjacent Ancestral Territory.

The Ancestral Territory comprises about 7.5 percent of the California coastline, spanning from the Little River to the south and Damnation Creek to the north. The traditional eastern boundary is Bluff Creek on the Klamath River and Hoopa Bluffs on the Trinity River.

"The health, well-being and culture of the Yurok people are intimately connected to the health of the Klamath River Basin ecosystem," the petition states. "Often self-described as salmon, water, forest and prayer people, the Yurok Tribe values management of, and reliance on, a traditional subsistence diet and practices, which are a vital part of the Yurok cultural identity.

"The Klamath River is often described as the lifeline of the Yurok Tribe."

The Port Gamble S'Klallam Tribe, also federally recognized, is based in Washington state and has about 1,200 members.

The tribe considers the use of 6ppd in tires as a violation of its treaty rights, signed in 1855. Port Gamble Bay is fed by multiple stream systems, many of which are outside the tribe's jurisdiction and do not have adequate buffers against stormwater runoff containing tire road wear particles.

As nearby Kitsap County continues to grow, the tribe believes the 6ppd/6ppd-quinone problem only will get worse, according to the petition.

The federally recognized Puyallup Tribe—translated from its native language as "the people from the bend at the bottom of the river"—live in Tacoma, Wash. The Puyallups have their own fisheries as they try to rebuild the depressed Chinook salmon populations.

A membership number was not known.

Today, the once abundant salmon and steelhead stocks in the Puyallup River Watershed (the Puyallup River begins high atop Mount Rainier in the Cascade Mountain Range) are a fraction of their historic populations.

Historically, the Puyallup River and its tributaries supported about 42,000 Chinook salmon; today that number is about 1,300 fish, according to the petition. Steelhead trout have gone from about 6,000 fish to about 1,500 adults in the rivers today.

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