The U.S. Tire Manufacturers Association (USTMA) and the U.S. Geological Survey (USGS) are partnering on a research project to assess and refine methods of evaluating potential alternatives to 6PPD for use in tires.
6PPD is an antiozonant (chemical) and antioxidant present in all motor vehicle tires on U.S. roads. The chemical serves critical safety and performance functions that protect motor vehicle tires from degradation upon exposure to ozone and oxygen in the air. It also provides critical needs for endurance and product safety. 6PPD was first developed in the 1960s and has been widely used in motor vehicle tires since the 1970s.
This USTMA and USGS collaboration marks another important step in the continuing efforts by tire manufacturers to look for possible 6PPD replacements. USTMA, through its 6PPD Alternatives Analysis Consortium, is preparing a report to meet requirements under the California Safer Consumer Products regulation by March 2024. Academic scientists in Washington state have conducted research that suggests 6PPD-quinone (6PPD-Q), a transformation product created when 6PPD interacts with ozone, is impacting the health of some fish species. 6PPD-Q is released into the environment as tires wear down while driving, and stormwater carries the chemical into nearby rivers and streams.
“Every day, with every partner we can, USTMA is pushing forward in the industry’s effort to identify potential alternatives to 6PPD, and we recognize that additional research is necessary,” said Anne Forristall Luke, USTMA President and CEO. “As USTMA continues its mission of advancing sustainability in the tire industry, our work with USGS will break new scientific ground, benefitting the environment, communities, researchers, and manufacturers alike.”
In this study, USTMA and the USGS Western Fisheries Research Center are working to establish a new method for in vitro toxicity testing of alternatives to 6PPD through a Collaborative Research and Development Agreement. The study will expose fish cell lines to rubber containing three possible alternatives to 6PPD and their transformation products. The toxicity of each proposed alternative will be assessed and compared to the toxicity levels of 6PPD-quinone.
An attractive component of this methodology is that it does not require testing on living fish. While this initial research is not expected to immediately identify a 6PPD alternative, each of the three alternatives represent a different class of chemical compounds and will inform future research. USTMA and USGS hope the results will help future researchers narrow their focus as the search for an alternative continues.
“The USGS is committed to working with federal, state, tribal, industry and other partners who share our scientific rigor to address this complex challenge,” said Michael Schmidt, Center Director at the USGS Western Fisheries Research Center. “This joint research with USTMA is one important piece of our work aimed at filling top-priority knowledge gaps, not only on potential 6PPD alternatives, but also in how to evaluate them with brand new investigative methods.”
The partnership between USTMA and USGS is set to run through September 2024. The organizations expect initial toxicological results to be available in March 2024.
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