Department of Ecology
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Urban runoff mortality syndrome (URMS), also known as Coho pre-spawn mortality, is a condition where Coho salmon die prior to spawning. It's directly related to urbanization density, specifically proximity to roadways—roadway runoff contains a mixture of chemicals that pollutes streams during rain events and is shown to cause URMS. 

While the source was narrowed to roadway runoff, UW and WSU scientists only recently identified the specific chemical responsible for URMS: 6PPD-quinone, a transformation product of 6PPD, which is used as an anti-degradant in almost every automobile tire on the road. 6PPD-quinone is toxic to Coho salmon at very low concentrations (less than 1 part per billion). Concentrations of 6PPD-quinone in urban streams in cities such as Seattle, San Francisco, and Los Angeles frequently exceed this level, particularly during storm events.

In 2021, the Washington State Legislature passed an operating budget proviso allocating $195,000 to Ecology to assess “potential hazards of 6PPD and other chemical classes and breakdown products used as antioxidants and/or antiozonants in tires.”

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The Department of Ecology is committed to providing people with disabilities access to information and services by meeting or exceeding the requirements of the Americans with Disabilities Act (ADA), Section 504 and 508 of the Rehabilitation Act, and Washington State Policy #188.

To request an ADA accommodation, contact Ecology by phone at 360-407-6700 or hwtrpubs@ecy.wa.gov. For Washington Relay Service or TTY call 711 or 877-833-6341. Visit Ecology’s website for more information.