Conservationists say that a chemical used by car tire manufacturers in the U.S. is leaching into waterways and killing protected fish species.
By Margaret Attridge, Courthouse News Service
A chemical additive in car tires is leaching into rivers and other waterways, killing protected fish species, lawyers for a conservation group and a fishing trade association told a federal judge during a bench trial in San Francisco, California, Monday.
After a three-day trial, the judge will determine whether tire manufacturers — including Bridgestone America, Goodyear Tires and Michelin North America — are violating the Endangered Species Act by harming protected and endangered fish species like coho salmon, steelhead trout and Chinook salmon.
The plaintiffs claim the tire manufacturers make or distribute products that contain an additive called 6PPD, a chemical that ultimately transforms into 6PPD-quinone when it reacts with ozone. As the tire interacts with the environment and roads, 6PPD-quinone leaches onto hard surfaces. When it rains, the chemical falls into rivers and other waterways, where it can kill fish in a matter of hours, they add.
After exposure, fish start displaying symptoms of urban runoff mortality syndrome, causing them to lose equilibrium and die within a few hours. Even if they’re transferred to non-polluted water before they die, they don’t recover from the syndrome, the plaintiffs say.
U.S. District Judge James Donato, a Barack Obama appointee, opened the first day of trial by cutting off the plaintiffs’ opening statements, opting to go right into witness testimony.
The plaintiffs’ primary witness, Edward Kolodziej, a scientist who studies urban runoff mortality syndrome, told the judge that tires are the main source of 6PPD-quinone in waterways and roadway runoff is likely to have high 6PPD-quinone concentrations.
He added that continued use of tires containing the chemical along the coast will cause harm or kill endangered coho salmon and other protected fish species, estimating that one car with four tires could theoretically create enough 6PPD-quinone to threaten the lives of an estimated 11 million coho salmon.
“6PPD-Q helps make tires more durable and crack less. When it reacts with ozone, 6PPD-Q forms on the surface of the tire; therefore, if the rubber surface gets wet, the 6PPD-Q leaches into water and moves with roadway runoff,” he said.
During Kolodziej’s testimony, the plaintiffs laid out how 6PPD-quinone was discovered and the effect it has on vulnerable aquatic populations.
Kolodziej said his team was contacted in 2018 after witnesses documented female coho salmon dying in urban streams before reproducing. His team identified a mortality signature for the chemicals that were present in the water when the fish perished, identifying the majority of the chemicals as derivatives from tire rubber. A 2021 study published by his team concluded that 6PPD-quinone was the primary toxic chemical in Urban Runoff Mortality Syndrome.
“It opened up our eyes that there are a lot of abundant tire rubber chemicals we knew little about,” he said. “Learning more and more about tires could explain this case of mortality.”
Kolodziej added that he was in communication with representatives from the tire industry throughout his studies, and in 2018, industry representatives met with scientists to discuss their latest findings.
“We did not want the industry to be surprised; they were obviously paying attention to our work,” he said.
In contrast, the defense’s main witness, Tiffany Thomas, a principal scientist at science consulting firm Exponent, testified that 6PPD-quinone is quick to degrade and has the opportunity to react with different chemicals and undergo many physical actions between the road surface and surface water.
She also testified that the concentration of 6PPD-quinone can vary widely depending on several factors, including storm conditions, the amount of organic carbon in the area and the path the water is subjected to, adding that any metrics of 6PPD-quinone concentration have to be “site-specific.”
“Without understanding all these factors, the ability to predict is speculation,” she said, adding that Kolodziej acknowledged the factors, but did not weigh them in his opinions.
“It’s not universally translatable to every location at every time,” she said.
Thomas further testified that the knowledge available on 6PPD-quinone was not enough to draw adefinitive line between the chemical and harmed fish populations.
“The data available on 6PPD-Q is inadequate to reliably predict the presence, phase, and concentration of 6PPD-Q in the streams and rivers in the salmonid populations identified in the complaint,” she said.
In a statement to Courthouse News, Sam Singer, a spokesman for the tire companies, said that “safety is the tire industry’s top priority.”
“For decades, 6PPD has been an essential ingredient in tires to prevent degradation and cracking that can jeopardize driver and passenger safety. There is currently no suitable alternative for 6PPD in tire manufacturing,” he said.
“The defendants remain committed to working with regulators and are actively participating in regulatory processes to identify a viable alternative to 6PPD. Any alternative must meet established standards for safety,” he continued.
Glen Spain, general legal counsel and northwest regional director of the Institute for Fisheries Resources and the Pacific Coast Federation of Fishermen’s Associations, told Courthouse News that families on the West Coast depend on salmon for their livelihoods.
“The use of 6PPD in tires has been shown to harm vulnerable salmon populations. Whether or not this should continue will be up to the court,” he said.
