In 2020, researchers at the University of Washington-Tacoma, Washington State University, and their collaborators identified the connection between car tires, 6PPD-quinone, and pre-spawn mortality in coho salmon. In response to this discovery, state agencies are taking action to protect humans and aquatic organisms from these chemicals. We’re also closely monitoring ongoing research and conducting our own research.  

We’re excited to provide updates on what state agencies are doing to address negative impacts of 6PPD and its breakdown chemical, 6PPD-quinone.  

Whether your day-to-day job is focused on all things 6PPD or you’ve never heard of the chemical until this blog post, we invite you to attend an upcoming webinar to learn more about the state’s response to 6PPD.

Presentations and written materials are available now so you can get up-to-speed on our current work. We’ll answer your questions during our live virtual event.  

Have questions? Get answers and learn more at our 6PPD webinar  

We know there are lots of questions about 6PPD, and we want to provide as much time as possible to answer them. We invite you to review 6PPD materials before the live session and submit questions using our online comment form. We’ll also take questions during the event.

Materials are available now from the following state agencies:

• Department of Ecology
• Department of Fish and Wildlife
• Department of Health
• Puget Sound Partnership
• Department of Transportation

Review the materials - including videos and written materials - online. 

After you’ve reviewed materials and sent in your questions, join our virtual event:

During this live event, we’ll provide a brief overview of 6PPD work and answer questions.

If we don’t get to answer your question during the webinar, we’ll answer it through our comment form. We’ll also create a summary  of frequently asked questions and answers to share on our email list after the event.

To stay up to date on Ecology’s 6PPD work, join our 6PPD and 6PPD-quinone email list and Stormwater 6PPD Subgroup email list.

What is 6PPD?

6PPD is a chemical used in tires to prevent cracking and tire blowouts. When 6PPD reacts with ozone in the environment to perform these functions, it creates 6PPD-quinone, a chemical that’s highly toxic to some aquatic organisms. For example, 6PPD-quinone leads to pre-spawn mortality in coho salmon, which means it kills salmon before they can lay eggs.

Learn more about 6PPD and Ecology’s ongoing response in our January 2023 blog post. 

Background on 6PPD and state agency work

We’re still learning about 6PPD and its impacts on aquatic organisms, humans, and the environment. State agencies are closely following research so we can stay as informed as possible. We’re also conducting and funding research of our own to help us fill data gaps. This research will inform our approach to protecting humans and aquatic organisms from the toxic effects of 6PPD and 6PPD-quinone.  

Our ultimate goal is to reduce sources of 6PPD-quinone, which requires finding a safer alternative to 6PPD to use in tires. In the short-term, stormwater best management practices can help reduce the amount of 6PPD-quinone that makes its way into creeks and streams.

Other state agencies are also engaging in critical work to address 6PPD, from staying up to date on the health impacts of 6PPD to identifying locations for stormwater retrofits. We look forward to sharing more about our work during the webinar.