Washington Tackles Puget Sound Toxins With Tire Chemical Ban

Washington state lawmakers are advancing bills that would eliminate one of the most persistent toxins threatening Puget Sound: a tire chemical called 6PPD that degrades into a deadly compound for salmon and other aquatic life. The identical House Bill 2421 and Senate Bill 6119 target the chemical directly, setting a 2035 deadline for manufacturers to stop selling tires containing 6PPD within the state.

The legislation addresses a growing crisis in the region's waterways. When 6PPD, a common rubber additive used to prevent tire degradation, enters stormwater systems and reaches marine environments, it converts to 6PPD-Q, a highly toxic substance that kills coho salmon and other species at remarkably low concentrations. Environmental advocates, including Puget Sound Keeper Foundation, have identified the chemical as a significant driver of coho population decline throughout the region.

The bills do more than ban the chemical outright. They specifically prohibit the use of regrettable substitutes—alternative additives that might simply shift the problem rather than solve it. This approach reflects lessons learned from previous chemical bans where industries replaced harmful substances with untested alternatives that proved equally damaging. By building in guardrails against such substitution, the legislation aims to ensure genuine progress in protecting Puget Sound's ecological health.

Support for the measures reflects growing recognition that controlling pollution at its source—rather than attempting to filter it out after it enters waterways—offers the most effective path forward. With coho salmon populations facing multiple stressors, from dam removal debates to ocean acidification, removing 6PPD represents a concrete step that Washington can control immediately. The legislation now moves through the committee process as the 2026 session progresses.