There is an additive called 6PPD added to tires to prevent them from degrading in the atmosphere, and it has been found that when this thing reacts with ozone in the air it forms another compound 6PPD-quinone which is highly toxic to some fishes. Weirdly enough it's highly toxic to some species of salmon but not to other salmon species.

Presumably there's work ongoing to find an less damaging replacement, but I haven't heard of any.

https://en.wikipedia.org/wiki/6PPD