A Tire Chemical is Threatening Salmon — Here’s What You Need to Know

By Rachel McCrea  |  Nov. 9, 2023  |  Washington Post

Whether you own a gas, hybrid, or electric car, driving may have some unexpected environmental impacts: It could be killing salmon.

Most tires contain 6PPD, a chemical several studies have linked to the deaths of certain kinds of fish.

In a lawsuit filed in U.S. District Court in California on Tuesday, they claim 13 major tire manufacturers, including Bridgestone, Goodyear and Michelin, are hurting and killing two species of salmon and one species of trout protected under the Endangered Species Act (ESA).

The lawsuit, filed by environmental group Earthjustice on behalf of the Institute for Fisheries Resources and the Pacific Coast Federation of Fishermen’s Associations, follows a decision by the Environmental Protection Agency earlier this month to review the chemical after a petition from three Native American tribes in California and Washington state.

“It is terrifying,” said Elizabeth Forsyth, Earthjustice’s lead attorney. “This is the biggest environmental catastrophe the world hasn’t woken up to yet.”

Here is what you need to know:

What is 6PPD?

6PPD is a chemical used in tires to help them last longer. When it comes in contact with ozone in the air, it turns into 6PPD-quinone.

6PPD-q is present on the surfaces of tires and in small particles on roadways, according to the EPA. When it rains, it gets washed into streams and rivers with storm-water runoff. That’s where it comes into contact with aquatic life.

How does 6PPD-q harm salmon?

In 2020, a study published in the journal Science linked the deaths of coho salmon in the Pacific Northwest to 6PPD-q. Other studies followed, including one in 2022 that suggested the chemical also harmed steelhead trout and Chinook salmon. That same year, another study found that two species of trout were sensitive to the chemical. Some of the fish in these studies, like sockeye salmon and white sturgeon, seemed unaffected.

What do salmon advocates want?

Earlier this year, the Yurok Tribe, Port Gamble S’Klallam Tribe, and Puyallup Tribe of Indians asked the EPA to prohibit the use of 6PPD in tires. West Coast ecosystems, as well as the tribes and the local economy, rely on salmon, which the chemical is killing, they said.

The EPA’s recent decision was in response to that petition. The agency said it is planning to study the chemical, including its effects on human health. The review is part of a rulemaking process that could lead to the ban of 6PPD.

What are tire manufacturers doing?

Tiremakers are trying to find an alternative to the chemical, according to the U.S. Tire Manufacturers Association, an industry trade group.

In a statement released on Nov. 3, the group said it “looks forward to continuing this effort by working with EPA to identify an alternative to 6PPD and to implement it on a time-frame consistent with public safety.”

The association, of which 12 of the 13 defendants are members, added that no alternative has been found yet that could meet federal safety requirements.

“We’re the nation that figured out how to put man on the moon,” Forsyth said. “It would shock me if we cannot create a tire that doesn’t kill up to 100% of coho salmon returning to urban watersheds.”

This article originally appeared in the Nov. 9, 2023, edition of the Washington Post.
Banner photo of salmon in Butte Creek (Sacramento River tributary) by Melina Mara, Washington Post.