These two steps bring a 6PPD replacement closer to market, as federal scientists will conduct extensive aquatic toxicity testing – a critical step toward final molecule selection and commercialization.
AKRON, Ohio, Aug. 27, 2026 /PRNewswire/ — Flexsys, a global leader in material science and advanced tire additives solutions, today announces two milestones in the effort to develop a 6PPD replacement for use in tires.
Following the November 2025 announcement that Flexsys has developed the world’s first viable alternative to 6PPD, the Company has now completed screening efforts and is focusing on two final candidate molecules for expanded testing and ultimately final selection as a replacement for 6PPD in tires. Both candidates sit outside the "PPD" chemical family, do not form a quinone transformation product during use and have met the Company’s ambitious safety, performance and environmental benchmarks in testing conducted in Flexsys labs, as well as with external industry partners.
Flexsys has also entered into a Cooperative Research and Development Agreement (CRADA) with the U.S. Geological Survey (USGS) to independently and thoroughly evaluate the two molecules’ potential effects on aquatic life. Building on Flexsys’ 2023 CRADA with the U.S. Department of Agriculture’s Agricultural Research Service (USDA-ARS), the testing performed under this USGS agreement is a critical step in determining the complete aquatic toxicity profile of these molecules, using novel test methodologies that extend well beyond what is typical for a new chemical registration. Under the agreement, USGS scientists will deploy existing and novel test methodologies while strictly adhering to USGS policies regarding scientific integrity.
"The tire industry has been waiting for two things: a molecule that actually works and independent proof that it is safe," says Carl Brech, Chief Executive Officer of Flexsys. "As of today, both are in hand or in motion. With tire and environmental safety testing underway, the focus has shifted from finding a potential replacement to thorough validation, regulatory approval, scale-up and industry adoption."
Any 6PPD replacement requires comprehensive safety and environmental testing beyond the standard requirements for new chemicals to provide tire manufacturers, tribes, regulators and all stakeholders with confidence in the selected alternative. As part of that effort, the USGS Western Fisheries Research Center (WFRC), with support from the USGS California Water Science Center and their Columbia Environmental Research Center, will evaluate molecules and their transformation products for effects on Pacific salmon and other aquatic species. The research conducted via this CRADA will pioneer novel test methods for assessing aquatic toxicity using cell-line research, creating new alternatives for aquatic toxicity testing that can be used to assess any chemical, not only 6PPD replacement molecules. Scientists at WFRC have already begun testing 6PPD alternatives from Flexsys; the CRADA expands and formalizes that work.
"This marks a significant milestone for our team, and we’re pleased to announce we’ve narrowed our efforts to two final molecules that continue to meet our strict targets for in-rubber performance, scalability, toxicity profile and environmental sustainability," said Neil Smith, Chief Technology and Sustainability Officer. "The selected alternative must be reliable and safe, not only today but for decades to come. USGS expertise provides independent evaluation with a level of rigor we could not execute on our own. We are proud to help pioneer novel toxicity-testing methods and eager to see the results."
Flexsys would also like to recognize external support for this work from the Economic Development Administration’s Tech Hubs Program, where Flexsys is a member of the Akron Sustainable Polymers Tech Hub, led by the Akron Chamber on behalf of the Polymer Industry Cluster, with associated support from Jobs Ohio.
"USGS has spent the past five years studying the effects of 6PPD on aquatic species and developing innovative methods to screen the safety of potential alternatives," said Michael Schmidt, Center Director, U.S. Geological Survey Western Fisheries Research Center. "For nearly a century, the Western Fisheries Research Center has provided objective science to support management of aquatic species across the Western United States."
Moving Toward Commercialization
Flexsys continues to optimize the process chemistry of both candidate molecules to allow for efficient world-scale production and continues its work with regulatory agencies globally to have the new chemistry approved for commercial use. Both candidates use substantially the same intermediate chemistry used to produce 6PPD today, allowing the industry to continue using existing chemical manufacturing assets: a factor that supports faster adoption and lower total investment cost.
ABOUT FLEXSYS
Flexsys is a global leader in advanced material-science solutions for the rubber and tire industry. Building on decades of chemistry and innovation expertise, the company develops and manufactures high-performance vulcanization, stabilization and protection systems that enhance the durability, safety and environmental performance of rubber products. Its portfolio includes Crystex™ vulcanizing agents, Santoflex™ antidegradants and Duralink™ HTS post-vulcanization stabilizers.
Operating across four continents with seven manufacturing facilities, a technology center in Akron, Ohio, Flexsys continues to pioneer next-generation solutions that drive performance and sustainability across the global tire industry.
For more information, please visit www.flexsys.com.
Forward-Looking Statements
This press release contains forward-looking statements regarding the development of Flexsys’ candidate 6PPD replacement molecules. These statements reflect current expectations and assumptions as of the date of publication and are not guarantees of future performance. Factors that could affect actual results include the outcome of ongoing research and testing, regulatory reviews and approvals, manufacturing and scale-up considerations, market acceptance, and other factors beyond Flexsys’ control. Flexsys undertakes no obligation to update any forward-looking statement, whether as a result of new information, future events or otherwise.
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