A chemical called 6PPD-quinone is shedding off every car tire on the road and causing mass die-offs of salmon.
April 26, 2026
Original Paper
When the rubber hits the road in Europe — A European risk perspective of 6PPD-quinone
SSRN · 6643251
The Takeaway
Car tires contain antioxidants to keep them from cracking, but these chemicals react with ozone to create a deadly byproduct. This substance washes into rivers during rainstorms and kills fish almost instantly. It was originally discovered in the Pacific Northwest, but researchers have now flagged it as a massive unmonitored risk for European waterways. The concentration of this toxin in urban streams often exceeds the levels needed to kill half the local fish population. Finding a safer replacement for this tire additive is now a matter of survival for entire aquatic ecosystems.
From the abstract
6PPD-quinone (6PPD-Q), a transformation product of the tire antioxidant 6PPD, is among the most acutely toxic chemicals to certain salmonids. Since its 2020 identification, it has been implicated in coho die-offs in the U.S. Pacific Northwest and prompted regulatory responses in North America. In Europe, however, awareness, monitoring, and risk assessment remain limited despite dense road networks, urban runoff, and sensitive fish communities. This Perspective synthesizes current knowledge and k