Tire anti-degradant (6PPD) and 6PPD-quinone

Tire on road making dust
6PPD stands for the chemical 6 p-phenylenediamine. It's a chemical that prevents automotive tires from degrading (i.e. breaking down) and helps them last longer. When 6PPD is exposed to air, it reacts with ozone to create 6PPD-quinone, pronounced like "qui-KNOWN," and also referred to as 6PPD-q. 6PPD-q is lethal to coho salmon and can contaminate water systems.

We work with tribal governments, local governments, state agencies, federal agencies, academic institutions, and industrial organizations to reduce the pollution and sources of 6PPD-q released from tires in Washington.

What are the impacts of 6PPD-q?

Driving causes tires to release dust and small particles because of friction on the road. These particles contain 6PPD-q, which then washes into stormwater, and, in turn, can spread to rivers, streams, and Puget Sound. Since 6PPD-q was only recently discovered, we are still learning about this chemical and its impacts on wildlife.

When rain falls on roads, 6PPD tire particles mix into runoff. Salmon are exposed to 6PPD. Green infrastructure can reduce exposure.

6PPD-q can end up in freshwater or marine environments harming wildlife. Green infrastructure can help remove toxic chemicals like 6PPD-q from stormwater.

Taking action to protect salmon

We’re initially focusing on three key efforts to effectively reduce the threat of 6PPD-q to salmon:

  • Understand the problem: Develop scientific methods to measure 6PPD-q in the environment and identify affected areas.
  • Reduce stormwater pollution: Identify stormwater-management approaches to treat 6PPD-q and tire debris before it reaches streams, update guidance for local governments to use, and increase funding for stormwater infrastructure.
  • Reduce sources of 6PPD: Research alternate chemical preservatives that could replace 6PPD in tires, and evaluate if these chemicals are actually safer.