EPA close to regulatory move on 6PPD tire chemical lethal to salmon

The EPA says its Office of Water is currently developing an analytical method for detection of 6PPD-quinone in surface and stormwater. Photo Credit: candy1812, stock.adobe.com

The U.S. Environmental Protection Agency (EPA) says it plans to change the Toxic Substances Control Act to address the environmental risks of 6PPD-quinone, an oxidation product of a common chemical used to prevent vehicle tire degradation.

6PPD can also be found in other rubber products such as footwear, synthetic turf infill, and playgrounds. The chemical reacts with ozone in the air to form a toxic byproduct called 6PPD-quinone (6PPD-Q).

The EPA’s announcement comes on the heels of the agency granting a petition on behalf of several U.S.-based First Nations tribes to ban 6PPD due to its proven lethality for coho salmon and other fish vulnerable to rubber wearing off tires and leaching into stormwater systems and water bodies.

“Today, EPA is responding to our Tribal partners by taking action to protect the coho salmon, which are a key part of the Tribes’ cultural identity and economic security,” announced Michal Freedhoff, assistant administrator for the Office of Chemical Safety and Pollution Prevention, in a statement. “These salmon and other fish have suffered dramatic decreases in population over the years. Addressing 6PPD-quinone in the environment, and the use of its parent, 6PPD, is one way we can work to reverse this trend.”

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The EPA intends to publish an advanced notice of proposed rulemaking under Section 6 of the Toxic Substances Control Act (TSCA), potentially to inform regulatory action. 

The agency also plans to finalize a rule under Section 8(d) of the TSCA to require 6PPD manufacturers, including importers, to report lists and copies of unpublished health and safety studies to the EPA by the end of 2024.

During testing, tire preservative 6PPD-quinone killed salmon within five hours of exposure to concentrations as low as 0.8 micrograms per litre, scientists found. Photo Credit: Bill Perry, stock.adobe.com.

In late 2020, Washington-based researchers discovered that minute concentrations of 6PPD-quinone in stormwater in the Pacific Northwest were found to be lethal to coho salmon after only a few hours of exposure. For decades, it was a mystery why 90% of salmon would die when migrating through urban streams in an attempt to spawn in the Seattle area. 

“The discovery that 6PPD is killing the fish in these waters could be exactly what saves salmon for us and all of the country,” said the Puyallup Tribal Council, one of the petitioners, in a statement. 

The EPA says its Office of Water is currently developing an analytical method for detection of 6PPD-quinone in surface and stormwater. Additionally, it is developing draft screening values for 6PPD-quinone and 6PPD to protect sensitive salmon and other aquatic life.

The agency is also coordinating with the National Science and Technology Council’s Joint Subcommittee on Environment, Innovation and Public Health on potential cross-governmental research on human health effects.

In Canada, the University of Saskatchewan has undertaken extensive research with grants from Fisheries and Oceans Canada worth some $600,000. The researchers studied how 6PPD-quinone impacts rainbow trout, arctic char, westslope cutthroat trout, lake trout and fathead minnows in Saskatchewan and Alberta.

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