The Impact of California's 6PPD Regulations on China's Tire Industry
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6PPD, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, with CAS number 793-24-8, serves as an antioxidant and antiozonant in tires, playing a crucial safety role by protecting tire components from erosion by ozone, oxygen, and other harmful factors. However, as tires wear against the road surface during driving, particles containing 6PPD are released, which can transform into the highly toxic 6PPD-quinone upon reaction with ozone, posing risks to aquatic life.


Regulatory Status of 6PPD in the United States

In August 2023, Native American tribes submitted a petition to the U.S. Environmental Protection Agency (EPA), requesting the establishment of regulations to completely prohibit the use, processing, application, and distribution of 6PPD in tire manufacturing. Following the tribes' appeal, the EPA responded in November of the same year, emphasizing the urgency of establishing risk management rules under the Toxic Substances Control Act (TSCA) to address the potential environmental risks posed by 6PPD. On March 8, 2024, the Washington state legislature officially passed Bill 5931, declaring that the replacement of 6PPD was inevitable.

Progress of Current Alternatives

On March 29, 2024, an alliance of 30 tire manufacturers, driven by USTMA, introduced the first phase of the 6PPD Alternative Analysis (AA) report under the California Safer Consumer Products Regulation (SCPR). Each member of the alliance submitted this report to the California Department of Toxic Substances Control (DTSC), which requires manufacturers selling tires in California to conduct an alternatives analysis to identify possible substitutes for 6PPD in tires. This preliminary alternatives analysis report lays the groundwork for further evaluation of alternative options. For automotive tires containing 6PPD, a strict, transparent, and science-based regulatory framework has been established to examine whether potential 6PPD substitutes meet tire safety and performance standards while improving environmental impact indicators. This includes compliance with Federal Motor Vehicle Safety Standards (FMVSS) and meeting the requirements of consumers, vehicle, and tire manufacturers. Over 60 potential alternatives to 6PPD have been identified, and after evaluation, screening, and scoring, five potential alternatives have been determined, though further assessment is needed:

Chemical Name















Specialized Graphene



Impact on China's Tire Industry

The United States is one of the significant export destinations for Chinese tires. Once a 6PPD alternative is determined, tire manufacturers will need to re-evaluate their product formulas to ensure compliance with the new regulations. This will require substantial investment in research and development resources and time, and it will also impact production costs and the supply chain. If the transition to new formulations is not timely, there is a risk that products may not be marketable, which could affect market share and profits.

CIRS C&K Testing has successfully developed a 6PPD detection method and now provides 6PPD testing services to a wide range of tire enterprises, helping businesses to reduce compliance risks.

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