The Chemical Killing Our Coho: The Problem with 6PPD-q
Washington is known for its iconic salmon runs, with salmon returning to our streams each year to spawn. But as they make their journey home, they encounter hidden dangers in the water. One of the most surprising comes from something we use every day and is quietly harming their populations.
6PPD and 6PPD-q Fast Facts
What is 6PPD?
6PPD is a chemical used in tires to prevent them from wearing down too quickly.
6PPD is used in all tires (cars, bikes, toys, planes, etc).
How does 6PPD turn into 6PPD-q?
When we drive, our tire dust contains 6PPD, which reacts with the air and transforms into toxic 6PPD-quinone or 6PPD-q.
How does 6PPD-q enter our waterways?
Rain! Rain carries any pollutants present in the environment, including toxic 6PPD-q, into nearby waterways.
How does 6PPD-q affect salmon?
Even small amounts of 6PPD-quinone can be lethal to coho salmon within hours of exposure, often before salmon are able to spawn.
In effect, 6PPD-q attacks salmon populations from two fronts: by directly harming fish and by preventing successful reproduction needed to make future generations of salmon.
How is Puget Soundkeeper tackling 6PPD-q?
On-the-Ground Action
Each fall, volunteers with Puget Soundkeeper come together at Longfellow Creek in West Seattle to monitor returning salmon during spawning season. The data collected through these surveys informs our efforts to eliminate 6PPD-q.
Advancing Policy Solutions
Puget Soundkeeper has worked with partners to secure funding for 6PPD research and support legislation that would ban tires containing 6PPD in WA state as soon as possible.
Influencing National Action
6PPD is found in all tires, everywhere, and affects aquatic life, everywhere. Puget Soundkeeper works with Congressional representatives and federal agencies, like the EPA, to advocate for urgent action to eliminate 6PPD from future tire production nationwide.
Latest News on Puget Soundkeeper and 6PPD-q
Reflections on the Nationwide Effort to Address Toxic 6PPD-q — Puget Soundkeeper (2026)
Puget Soundkeeper: Report reveals how urban runoff continues to threaten coho salmon health — My Edmonds News (2026)
Puget Soundkeeper Public Testimony in Support of HB 2421: Concerning 6PPD and regrettable 6PPD substitutes in tires — WA House Environment & Energy Committee (2026)
6PPD: Tires, Toxic Stormwater, and Salmon Don’t Mix — Puget Soundkeeper (2021)