6PPD | 6PPD-quinone

6PPD is an organic compound. Since the 1960s it has been used as a chemical additive to help preserve the rubber in tires. One unexpected side-effect has been that, as tires degenerate through use, particles of 6PPD shed and react with ground level ozone to form 6PPD-quinone. In 2020, scientists traced 6PPD-quinone as the toxic culprit for wide-spread salmon die-off across the Pacific Northwest. How? After rains, storm water runoff carries 6PPD-quinone to area rivers, streams and creeks, home to salmon and other living things. It turns out that 6PPD-quinone is highly toxic to some animals and that young coho salmon die within hours after exposure, devastating the life cycle of salmon. This reaction reverberates exponentially and affects regional ecosystems and the indigenous communities and cultures who live there. 

One result of the work of tribal educators, scientists, and other activists to highlight 6PPD as a toxic hazard is that In Fall 2023, the California Department of Toxic Substances Control (DTSC) instituted new regulations that will require tire manufacturers to seek alternatives to 6PPD.