Washington Passes Legislation to Phase Out 6PPD

In March 2024, Washington enacted SB 5931, addressing the chemical 6PPD in motorized vehicle tires. This made Washington the first state to pass legislation to regulate 6PPD. The bill, sponsored by Senator Jesse Salomon, aims to reduce sources and uses of 6PPD in Washington to protect aquatic life, particularly salmon. 

• Why It Matters: 6PPD is a chemical used to keep motor vehicle tires flexible and make them last longer. When 6PPD is exposed to air, it reacts with ozone, creating 6PPD-quinone (6PPDQ). Driving creates friction, releasing tire dust containing 6PPDQ. The 6PPDQ runs off and contaminates water systems, making it particularly lethal to coho salmon. 6PPDQ has been identified as the second most toxic aquatic chemical ever measured, causing rapid mortality to species of cultural and environmental significance. 
• Implementation Status: As part of the Safer Products Program, 6PPD is now in the second of four phases of regulatory action: identifying consumer products that contain 6PPD. On November 1, 2024, Washington’s Department of Ecology published the Safer Products for Washington Cycle 2 Draft Identification of Priority Products Report to the Legislature. The report highlights artificial turf and motor vehicle tires as priority products. The final priority products report will be published June 1, 2025. 

Key Components of the Bill

• Identifies 6PPD as Priority Chemical and Tires with 6PPD as Priority Consumer Products: This sets into motion the first phase of regulatory action on 6PPD.
• Part of Washington’s Safer Products Program: The Safer Products Program works with the Toxic Pollution Law to create a pathway to keep harmful chemicals out of the environment, reduce the use of toxic chemicals in consumer products by restricting or eliminating those chemicals when safer alternatives are available, and to regulate chemicals in consumer products in five-year cycles.  
• Sets Out a Timeline for Regulatory Action: Under the Safer Products Program, there are four phases in a five-year regulatory cycle: selecting priority chemicals and classes, identifying consumer products that contain these chemicals, determining the nature of appropriate regulatory action, and rulemaking. 

Bill Sponsors

The bill was led by Senator Jesse Salomon. Other co-sponsors included Senator Andy Billig, Senator Liz Lovelett, Senator Jamie Pedersen, and Senator Sharon Shewmake.

State and Federal Context 

Other than Washington, only California has taken steps to regulate 6PPD in motor vehicle tires. In October 2023, the California Department of Toxic Substances Control (DTSC) identified tires that contain 6PPD as a priority product under the state’s Safer Consumer Products (SCP) program. This begins a multi-year process for tire manufacturers to disclose their use of 6PPD and provide a series of analyses on safer alternatives.

On the federal level, this year the EPA developed an agency-wide Action Plan for 6PPD and 6PPDQ to coordinate research and funding with federal partners, Tribes, states, and industry. In November 2024, the EPA put out an advance notice of proposed rulemaking (ANPRM) under Section 6 of the Toxic Substance Control Act (TSCA), seeking public input on 6PPD and 6PPDQ. 

Looking Ahead

Washington is currently researching safer alternatives to 6PPD for motor vehicle tires. For more resources and to keep up with Washington’s research and regulatory work, Washington maintains an extensive 6PPD resource page.