With this commitment, USTMA members continually look for new ways to improve both their products and operations and their understanding of the impact of tires on the environment. At the same time, USTMA members are committed to producing the safest, most durable and high-performing tires possible.
Tire and Road Wear Particles
The grip between a tire and the road surface is essential to tire safety and performance, and this critical grip also leads to abrasion of both tire and road surface, producing tiny debris called tire and road wear particles (TRWP). TRWP are a mixture of tire tread and road pavement material.
Since 2005, USTMA and its members have supported peer-reviewed scientific studies related to TRWP conducted by the Tire Industry Project (TIP), organized under the World Business Council for Sustainable Development (WBCSD). TIP has assessed potential environmental and human health impacts associated with particles from tires. The published literature shows that the outcome of toxicity studies for tire-related particles have been highly variable and depends on the test material used in the study, species tested, exposure concentrations, and endpoints evaluated. Studies of the acute and chronic toxicity of TRWP using recommended freshwater species show low risk of toxicity under environmentally relevant conditions.
USTMA supports additional research on TRWP that considers the latest science and most comprehensive methodologies, such as those developed by TIP, to gain a deeper understanding of any potential human health or environmental risks associated with TRWP.
USTMA also supports improvements in tire design and consumer efforts to reduce tire wear and advocates for green infrastructure that reduces TRWP generation and mitigates its impact in stormwater runoff.
For information on TRWP and USTMA’s actions, see Tire and Road Wear Particles.
6PPD and Tire Manufacturing
All USTMA members use a chemical additive called 6PPD to help tires resist degradation and cracking, which is vital for driver and passenger safety. In December 2020, a report published by researchers at the University of Washington and the Washington Stormwater Center (Tian et al.) identified a 6PPD transformation product that they called 6PPD-Qquinone and concluded that it is toxic to coho salmon and may be causing urban runoff mortality syndrome in this fish species. Earlier studies of 6PPD transformation products had not identified this substance.
USTMA and its members are committed to collaborating with researchers and regulators to better understand these distinct compounds (6PPD and 6PPD-Qquinone), resolve knowledge gaps and determine appropriate steps to ensure continued driving and environmental safety.
For information on the actions the USTMA has taken on this issue, see 6PPD and tire manufacturing.
Zinc and Tires
The tire industry uses zinc to produce safe and durable tires. While scientific studies have concluded that current uses of zinc have low potential for environmental effects, USTMA and its members remain committed to collaborating with researchers and regulators to understand and address any potential impacts of zinc on the environment.
For information on zinc in tires and USTMA’s position, see Zinc and tires.
Among the many materials used to make tires is a high-quality grade of steel that provides strength, high load-carrying capacity, puncture resistance and durability. Access to this important material is critical to the U.S. tire manufacturing industry.