For years, a mysterious phenomenon called “urban runoff mortality syndrome” has been decimating salmon returning to freshwater streams to spawn in the Pacific Northwest. The syndrome can kill up to 100% of salmon in an affected area before they are able to spawn and lay their eggs. Now, researchers have finally solved the mystery. The culprit is our tires. Or, more specifically, a chemical called 6PPD used in tires since the 1950s to prevent degradation. During normal use, tires made with 6PPD release a breakdown product known as 6PPD-q, which washes into waterways during storms. 6PPD-q is the second most toxic chemical to aquatic species ever evaluated. To put an end to this existential threat to wild salmon populations, the Yurok, Port Gamble S’Klallam, and Puyallup Tribes are petitioning the Environmental Protection Agency (EPA) to establish regulations prohibiting the manufacturing, processing, use, and distribution of 6PPD for tires. Read ON.