Comment: Tire dust killing salmon; state must bar chemical’s use

Published 1:30 am Saturday, February 14, 2026

By Andrew M. Kenefick / For The Herald

Fall rains send stormwater — and everything in that stormwater — off our roads into nearby creeks and streams — just as coho salmon head upstream.

Many — often more than 90 percent — will die before they can spawn. In the spring, rainstorms will flush toxins off roadways into creeks where juvenile salmon are emerging and rearing. They, too, will die at alarming rates; recently estimated at 80 percent on Miller Creek in Normandy Park, west of SeaTac. This cycle has repeated for decades. Yet only recently have we known the cause: stormwater contaminated with the compound 6PPD-Q.

Since the 1960s, the chemical 6PPD has been used in nearly every vehicle tire sold in the United States to prevent cracking and degradation of the tires. Once in the environment, however, 6PPD transforms into a pollutant called 6PPD-Q, so toxic that just a few ounces can decimate juvenile and adult coho salmon. Every time we drive, tiny bits of tire wear off and wash 6PPD-Q into streams.

Washington researchers have led ongoing efforts to understand the impact of 6PPD-Q on our native fish, and we should also be the first state to lead the solution. A ban on the sale of tires containing 6PPD would protect our salmon and other aquatic species from this lethal roadway toxin. And this is not just a Pacific Northwest or coho issue. Worldwide research continues to identify other aquatic species at risk from 6PPD-Q contamination, including coastal cutthroat trout (native to Washington), rainbow trout, Eastern brook trout, and lake trout, species valued throughout the nation. The science is clear, the damage ongoing, and the answer long overdue: banning 6PPD in tires will accelerate progress toward a solution.

While Washington already designates 6PPD as a “priority chemical,” the state’s existing regulatory processes are cumbersome and require lengthy rule-making with no certainty in outcome. This is precisely why legislation introduced by state Rep. Zach Hall, D-Issaquah, and state Sen. Marko Liias, D-Edmonds, is so important. House Bill 2421 and Senate Bill 6119 will make Washington the first state to prohibit the sale of new tires containing 6PPD.

Safety is paramount. Recognizing the need to ensure new tires are safe for Washington drivers, the bill sets a 2035 deadline to provide ample time for research, testing and adoption of a replacement for 6PPD.​

Tire manufacturers and allied lobbyists argue that a ban is premature, alternatives need more testing, stormwater controls are sufficient, and a proposed fee is too expensive. These are familiar tactics; similar claims were made against restrictions on lead in gasoline and copper in brake pads before Washington and other states acted.

Washington’s copper brake law — also once criticized as unworkable — spurred innovation, was implemented smoothly and shaped nationwide standards. A 6PPD ban can do the same: send a clear market signal, reward early innovators and accelerate safer tire chemistry nationwide. We ought to be optimistic that this can be done. In fact, the largest U.S. producer of critical tire additives, announced this past November that it has developed the industry’s first viable alternative to 6PPD that meets tire safety standards, can be readily deployed, and will meet Washington’s environmental requirements.

Green infrastructure and stormwater treatment are crucial for limiting localized impacts to fish and other wildlife, but the scale of the problem — runoff from every roadway, parking lot and driveway — is massive, expensive and perpetual. Treatment alone will never fully solve a problem built into the product itself. Prevention is the only real solution: Phase out 6PPD, incentivize innovation and require transparency about replacement chemicals. The Liias and Hall bills offer exactly that path, balancing an urgent need to protect salmon with a realistic timeline for manufacturers and retailers to ensure driver safety and environmental protection.

Salmon are more than a Pacific Northwest icon; they are central to this region’s identity, economy and obligations under treaty and state law. By enacting a ban on 6PPD‑containing tires this session, the Washington Legislature can match its commitment to salmon recovery with real action; and ensure that every road in this state is no longer a conduit for a chemical poisoning our streams and killing our fish.

Andrew M. Kenefick is the chair of the Advocacy Committee for the Washington Council of Trout Unlimited.