We are encouraged by the federal government’s decision to grant our request to prioritize the tire chemical 6PPD for assessment

This is an important first step towards regulating this toxic chemical.

6PPD is an additive that manufacturers use to prevent tires from degrading. Over time, tires release particles and chemicals that enter waterways.

The breakdown product of 6PPD, called 6PPD-quinone (6PPD-q), has been linked to mass deaths of coho salmon when they pass through urban streams. An estimated 40-90 percent of adult coho salmon returning to spawn in urbanized watersheds could die from exposure to this chemical each year. 

Since a seminal study in December 2020 first identified 6PPD-q as the cause of coho deaths in Washington State, similar impacts are being observed in other fish, including rainbow trout and lake trout. The full scope of harm is unclear, but the lethal effects of 6PPD-q requires urgent action and government regulation. 

In February, Ecojustice, on behalf of Raincoast, Watershed Watch Salmon Society, and Pacific Salmon Foundation, formally requested the federal government assess the harms caused by 6PPD, a chemical linked to mass die-offs of coho salmon. 

Prioritizing 6PPD for assessment under the Canadian Environmental Protection Act (CEPA) is a crucial step to ensuring 6PPD is regulated and coho salmon are protected. Environment and Climate Change Canada has committed to releasing their plan to prioritize assessments by June 2025, and a regulatory intervention – should it proceed – would occur at a future date to be determined. While there is no set timeline for regulatory intervention under CEPA, an expedited assessment is strongly needed to protect salmon.

The response from the federal government

The federal government has granted our request on April 30, 2024, to prioritize the tire chemical 6PPD for assessment, an important first step towards regulating this toxic chemical. We are encouraged by this response. However, we feel that regulatory intervention is needed now. Without prompt action, tires will continue to release 6PPD and its breakdown product 6-PPD-q into fish habitat and kill salmon for years to come.

Background information 

  • This is the first time the Section 76 amendment to the CEPA legislation has been used to successfully request prioritization. It is also the first time Canada has taken action to address 6PPD.
  • When 6PPD comes into contact with ozone in the air it turns into 6PPD-quinone (6PPD-q), highly toxic to coho salmon. While the source of mass coho deaths in urban areas was unknown for decades, a seminal 2020 study confirmed 6PPD-q as the cause
  • Through tire wear on roadways, 6PPD particles make their way into urban rivers and streams through rain run-off, turning waterways toxic.    
  • 6PPD has also been found in sediments and soils, household dust, and human urine.  

You can help

Raincoast’s in-house scientists, collaborating graduate students, postdoctoral fellows, and professors make us unique among conservation groups. We work with First Nations, academic institutions, government, and other NGOs to build support and inform decisions that protect aquatic and terrestrial ecosystems, and the wildlife that depend on them. We conduct ethically applied, process-oriented, and hypothesis-driven research that has immediate and relevant utility for conservation deliberations and the collective body of scientific knowledge.

We investigate to understand coastal species and processes. We inform by bringing science to decision-makers and communities. We inspire action to protect wildlife and wildlife habitats.

Coastal wolf with a salmon in its month.
Photo by Dene Rossouw.