a recent study found that an additive in tires called 6PPD, when exposed to oxygen and ozone, morphs into 6PPD-quinone, a toxic chemical that quickly killed 90 percent of young salmon in laboratory tests.

Every day, thousands of cars take to the highways, constantly shedding tiny particles of rubber from their tires, which, when it rains, are washed down into the Bay. That seemed normal until something caught the attention of researchers at the SF Estuary Institute.

"About 5 years ago we learned of this study that was being done up in Washington State that found large quantities of salmon die off as a result of this chemical additive in tires," said Warner Chabot, the Institute's Executive Director.

The California Department of Toxic Substances Control agreed and recently put tire manufacturers on notice that they need to find a safer alternative--which currently doesn't exist. The problem is, 6PPD is extremely important as a preservative that keeps tires from drying out and crumbling. Without it, tires could quickly become a safety hazard.

And rather than fight the issue, the US Tire Manufacturers Association is leaning into the challenge. In a statement, they acknowledged the problem and said, "We are committed to collaborating with researchers and regulators in California and Washington to better understand this material, fill knowledge gaps and determine next steps."

"We are dancing on the edge of extinction for salmon in California," said Chabot. "Anything and everything we do is important and urgent and necessary."

The timeline is pretty tight. The State has given manufacturers until March of next year to at least submit a study of possible alternatives or face having their tires taken off the market in California. So, the race is on to find chemicals that can help, rather than harm, the environment.

https://www.cbsnews.com/sanfrancisco/news/tire-additive-could-push-california-salmon-to-extinction-study-says/