Urgent Call for Ottawa to Ban Salmon-Killing Tire Chemical 6PPD-Quinone
Every autumn in British Columbia, thousands of coho salmon undertake their remarkable journey from the ocean back to freshwater streams and creeks to spawn. However, in many urban waterways across the Greater Vancouver Area, this homecoming ends tragically with dozens of dead fish reported annually.
The Gruesome "Dance of Death"
Researchers have documented what they describe as a disturbing "dance of death" among affected coho salmon. The fish exhibit distressing symptoms including gasping for air, erratic swimming patterns, and flipping onto their backs. Within mere hours of exposure, these salmon perish completely.
For years, scientists were baffled by these regular reports of dying coho, eventually labeling the phenomenon "urban run-off mortality syndrome." Various potential causes were investigated including:
- Road salts and de-icing chemicals
- Metals from automotive brake pads including copper and zinc
- Pathogens and waterborne diseases
- Hydrocarbons from vehicle emissions
While salmon are sensitive to all these contaminants, none adequately explained the mysterious deaths occurring in British Columbia's waterways.
The Toxic Culprit Revealed
The mystery was finally solved in 2021 when researchers identified the causal agent: 6PPD-quinone. This chemical forms when a common tire additive called 6PPD reacts with ozone in the atmosphere. Manufacturers add 6PPD to tire rubber to prevent cracking and extend tire lifespan.
When rainfall washes tire particles from roads into streams and creeks, this toxic compound enters salmon habitats, severely impacting coho salmon populations and other salmon species. The chemical's potency is staggering—at concentrations of just 41 parts per trillion, 6PPD-quinone proves lethal to coho salmon within 24 hours.
"To put this in perspective," explains the research, "this concentration would be equivalent to adding just 41 drops of 6PPD-quinone to 35 Olympic-sized swimming pools and killing half the coho salmon exposed."
Additional Sources of Concern
A recent University of British Columbia study has revealed another disturbing source of this chemical contamination. Artificial turf sports fields made from crumb rubber derived from discarded vehicle tires are discharging significant and persistent amounts of 6PPD-quinone into surrounding environments, creating additional threats to salmon habitat.
Federal Inaction Despite Commitments
In March 2025, the federal government committed to prioritizing 6PPD for an updated toxicity assessment under Canada's cornerstone environmental legislation, the Canadian Environmental Protection Act. However, researchers have been surprised to learn that another full year could pass before even the first phase of this assessment is completed.
Compounding this delay, the funding that Environment and Climate Change Canada relies on to conduct these critical toxicity assessments has yet to be renewed. This lack of urgency from Ottawa comes despite mounting evidence of the chemical's devastating effects on vulnerable salmon populations.
The Growing Threat of Tire Pollution
The problem of tire wear is poised to increase significantly on Canadian roads as electric vehicles become more prevalent. These heavier vehicles, due to their substantial battery systems, shed more tire particles than conventional cars, potentially exacerbating the runoff of 6PPD-quinone into aquatic ecosystems.
Scientists and environmental advocates are now demanding immediate federal action to address what they describe as one of the most toxic chemicals salmon encounter in their habitats. The survival of British Columbia's iconic coho salmon populations may depend on how quickly Ottawa responds to this environmental crisis.
