WASHINGTON, July 7 — A chemical found in virtually every tire on the road is now under scrutiny for a potential link to Alzheimer’s disease, a finding that could reshape the $258.2 billion global tire industry and add new pressure on manufacturers already racing to find safer alternatives. The substance, 6PPD, has been a standard ingredient in tire rubber for decades, preventing cracking and extending tire life. But a study published in 2024 identified a possible connection between 6PPD-quinone, a transformation product of the chemical, and Alzheimer’s.
The research has landed at a moment when the U.S. tire industry, which employs more than 100,000 workers according to the U.S. Tire Manufacturers Association, is already confronting regulatory and environmental questions about the compound. ## The chemical at the center 6PPD is added to tire rubber to protect it from ozone and oxygen degradation. When tires wear down on roads, the chemical is released into the environment and can transform into 6PPD-quinone, or 6PPD-Q.
That derivative has already been linked to mass die-offs of coho salmon in Pacific Northwest waterways, triggering state and federal investigations. The new Alzheimer’s research, published in 2024, raises questions about whether the same compound could pose risks to human health. The study’s authors did not establish that 6PPD-Q causes Alzheimer’s, but the potential association has drawn attention from public health researchers and investors alike.
The Alzheimer’s Association estimates the disease cost the U.S. economy $345 billion in 2023, covering healthcare and long-term care expenses. That figure is projected to climb to $1 trillion by 2050 as the population ages.
Even a modest link between a ubiquitous environmental chemical and Alzheimer’s could carry enormous public health and economic implications. ## Industry response and the search for alternatives The U.S. Tire Manufacturers Association has committed to finding a safer alternative to 6PPD by 2025. That deadline is now less than a year away, and the Alzheimer’s findings may intensify the pressure on tire companies to deliver. The cost of replacing 6PPD in tires remains unknown, but industry analysts say the effort will involve significant research and development expenses.
The chemical is used in virtually all tires globally, making its replacement a major industrial challenge. Reformulating tire compounds to maintain performance, safety, and durability without 6PPD is not a simple substitution. Grand View Research valued the global tire market at $258.2 billion in 2022 and projected growth to $364.7 billion by 2030.
Any regulatory action that forces reformulation across that entire market would represent one of the largest industrial chemistry transitions in decades. ## What comes next The 2024 study’s publication may influence investor sentiment toward tire manufacturers and related chemical producers. Regulatory agencies have not yet announced new rules regarding 6PPD or 6PPD-Q, but the combination of environmental toxicity and potential human health concerns creates a powerful case for action.
Tire companies face a complex equation. They must balance the cost and difficulty of developing new chemical stabilizers against the risk of future litigation, regulatory fines, or market pressure from consumers and investors who demand safer products. For the more than 100,000 American tire industry workers, the transition carries both risk and opportunity.
New manufacturing processes could create jobs in research and development, but the cost of reformulation could also squeeze margins and lead to consolidation. The USTMA’s commitment to finding a safer alternative by 2025 now takes on added urgency.
Whether the industry can meet that deadline while maintaining tire performance and affordability remains an open question. The Alzheimer’s research adds a new dimension to an already complex environmental and industrial puzzle. What began as a story about salmon in Pacific Northwest streams has become a question about the air we breathe, the roads we drive, and the chemicals embedded in the products we use every day.
