Our View: 6ppd and 6ppd-quinone are separate but equal

Separate are the notions of wildlife protection and driver safety, but finding a way to maintain both is of equal importance.

Such is the dilemma for the California Department of Toxic Substances Control and the U.S. Tire Manufacturers Association.

As the study of the protective tire additive 6ppd—and its transformational product, 6ppd-quinone, found to be harmful to coho salmon in the Puget Sound area of northern California—continues, both entities have made their priorities clear.

The USTMA, which counts 12 of the largest tire manufacturers in the world as members, has stated it will work with the DTSC, a division of the California EPA, in studying a possible alternative to 6ppd, a critical antidegradant and antiozonant in preventing tire cracking and wear.

For the USTMA's part, consumer safety implications are clear and present.

The DTSC, in turn, follows a set of pre-determined guidelines in examining any "priority product" on its Safety Consumer Product Regulations list, with 6ppd placed there precisely because it is inimical to coho salmon.

The species has its place in Native American history for both sustenance and culture, and it is prized as a fishery in the Pacific Northwest.

As such, environmental implications are evident for the DTSC.

In its general process, the DTSC analyzes an overall list (containing chemicals from almost every industry, including cosmetic, medical, cleaning and manufacturing, among many others) that is "of concern;" conducts a public comment phase; prioritizes chemicals that may cause harm; undertakes an alternatives analysis; and offers a range of regulatory action (or nothing at all).

The DTSC is expected to finalize the listing of 6ppd in tires as a priority product—a listing that the USTMA recently supported—sometime in early 2023.

Words also matter.

Just as critical as the outcome of the alternative study is the choice of language, drawing distinctions between 6ppd, 6ppd-quinone and tire road wear particles.

To wit: 6ppd is a tire additive that is critical to consumer safety, and 6ppd-quinone is a transformational product of as-yet unknown origin, forming somewhere between tire abrasion and California's waterways.

And TRWP, which can contain 6ppd-quinone that ultimately finds its way into urban runoff, is 50-percent tire tread and 50-percent road surface.

This is precisely where the DTSC and the USTMA seem to bifurcate in their missions, bending toward argument and rebuttal and away from call and echo.

While the USTMA, in making cryo-milled TRWP available for study, is prioritizing how 6ppd-quinone forms, the fact that 6ppd-quinone exists at all (and contains 6ppd) is driving the DTSC in its process.

Discovering how 6ppd-quinone forms—the USTMA correctly notes that greener road construction, with gutters or other avenues for roadway runoff, should be part of the overall conversation—and finding an alternative to the foundational additive 6ppd are critical issues.

The outcome of the DTSC process could have far-reaching implications for consumer and aquatic safety, and any precedence set in mandating an alternative to 6ppd could reach well beyond the West Coast.

Results of this complex alternative analysis cannot be either consumer safety or environmental protection—continued cooperation will be required to produce both.