west coast fishers and conservationists allege that a chemical additive used in tires is polluting rivers and waterways, killing coho salmon and other fish.

The case was initiated after the apparent solving of a decades-old mystery: what was causing mass deaths of endangered coho salmon in the Pacific north-west as they returned to streams to spawn. The deaths happened after heavy rain.

Scientists, suspecting storm runoff, described the phenomenon as “urban runoff mortality syndrome”.

It took years for scientists from Washington State University to pinpoint what they now allege is the chemical culprit. In 2020, they published a study in Science that claimed to solve the mystery: they found a toxic substance in leachate from car tyres that killed the fish. Known as 6PPD-quinone or 6PPD-q, it is an oxidation product from 6PPD, a chemical added to car tyres to prevent them breaking down.

The judge will determine whether the tyre manufacturers are violating the Endangered Species Act by harming fish species, including coho salmon, protected under the legislation.

https://www.theguardian.com/environment/2026/feb/02/is-tyre-pollution-causing-mass-deaths-in-vulnerable-salmon-populations

I'm sure you're away that tires wear away, and that's evident by them going bald, and the amount of tire that disappears, is ground off by the asphalt and concrete that we drive on, plus sand and gravel. Every time it rains, all the tire dust is washed away, and heads down the roads, sidewalks, yards, ditches, culverts, streams, and then accumulating amounts are then hitting the rivers