The California Department of Toxic Substances Control has proposed a rule that would require tire manufacturers to consider safer alternatives over research that has linked a highly toxic tire chemical to salmon deaths in the Pacific Northwest.
A 2020 study identified that the chemical 6PPD, which is designed to give longevity to tires, as the reason behind decades of salmon fatalities within Washington state. The chemical was also identified within waters in California, including in Langunitas Creek, which contains a substantial population of endangered coho salmon.
“The recent research linking 6PPD to coho salmon deaths is extremely compelling,” the department director Meredith Williams said, adding that “It is clear that particles containing this chemical are entering our waterways. This is also a national issue. California is taking a leadership role in protecting our fish, our environment and the cultural heritage of Native American tribes with rich salmon fishing traditions.”
The new rule, which is seeking public comment through July 5th, would not ban the chemical but would require tire manufacturers to investigate if there are alternative chemical. If backed by the public, the state would aim to have the rule come into effect in 2023.
The chemical infiltrates waterways after breaking up on roads and mixing with ground-level ozone to create a new compound, known as 6PPD-quinone, before washing into rivers when rain falls in the area.
The 2020 study warned that the toxic chemical could kill coho salmon with four hours of exposure. It used tire samples from the US Tire Manufacturers Association in Washington DC. The association supported calls from environmental groups in calling on the state to review the use of the chemical.
“We remain committed to collaborating with researchers, regulators and stakeholders to fill these knowledge gaps and help find a viable alternative to 6PPD that does not compromise tire performance or driver safety and also ensures environmental safety,” Sarah Amick, Vice President of the US Tire Manufacturers Association said.
Despite the study and support from the US association, local monitoring group’s in the region suggested the chemical does not appear to have caused any die-offs of coho salmon, claiming it is “not a dramatic concern currently.”
“We don’t see direct mortality with it,” Preston Brown, water conservation director of the Olema nonprofit, adding that “We don’t see the high degree of adult mortality like some of the other watersheds like Puget Sound do see.”
