On the heels of its November 2023 commitment to gather information on the common tire additive 6PPD - and its chemical by-product 6PPD-quinone – that could be used to inform a subsequent regulatory action, the U.S. Environmental Protection Agency announced today the publication of a draft testing method (EPA Method 1634) that will enable government agencies, Tribes, and other groups to determine where and when 6PPD-quinone is present in local stormwater and surface waters. The 6PPD-quinone draft method is now available at https://www.epa.gov/cwa-methods.

“We heard from the Tribes and other governmental agencies that one of the highest priorities for the agency should be the rapid development of a test for 6PPD-quinone,” said Casey Sixkiller, Regional Administrator of the agency’s Region 10 office in Seattle. “In what seems like lightspeed, the agency has delivered. The faster we can identify where problems exist, the faster we can correct them. I’m quite proud of our team.”

Used for more than six decades in tires, 6PPD is also found in other rubber products such as footwear, synthetic turf infill, and synthetic playground surfaces. 6PPD reacts with ozone in the air to form 6PPD-quinone, which EPA-funded research in 2020 found to be linked to the deaths of coho salmon in urban Puget Sound streams. Exposures occur when runoff containing the chemical is washed from parking lots and streets into streams and other bodies of water.

The agency is funding several research initiatives to fill data gaps on 6PPD-quinone, including the development of an analytical method.

Widespread availability of a draft EPA analytical method for 6PPD-quinone provides tribes and local governments with an important tool for better understanding stormwater and surface water quality, to inform how and where to put in place protections for sensitive salmon, trout, and other aquatic life from potentially dangerous runoff. The agency’s draft testing method is available for use now.

Additional research

EPA is continuing to fund and conduct research activities to expand its understanding of the impacts of 6PPD-quinone, and to fill data gaps. For instance:

  • The agency’s Office of Research and Development is investigating fate and transport of the chemicals in air and water, ecotoxicity, mitigation strategies including green infrastructure solutions for stormwater contamination, and measurement development research for multiple media (e.g., air and sediment).
  • EPA’s Office of Water is developing draft screening values for 6PPD-quinone and 6PPD in water that are protective of sensitive salmon and other aquatic life; the values can be used by many parties to evaluate monitoring results, and Tribes and states could also consider using the values in their water quality protection programs.
  • 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 of 6PPD-quinone.

To learn more, visit EPA’s new 6PPD-quinone webpage developed to keep the public and stakeholders updated as research progresses, alternatives to 6PPD are identified, and ways to mitigate the effects of 6PPD-quinone on the environment are implemented.