The environmental ubiquity of tire and road wear particles underscores the need to understand the occurrence, persistence, and environmental effects of tire-related chemicals in aquatic ecosystems. One such chemical is 6PPD-quinone, a transformation product of the tire antioxidant 6PPD. 6PPD-quinone is one of the most toxic known chemicals to aquatic animal life and is the causative agent for coho salmon prespawn mortality. We present results from the first national surface water reconnaissance of 6PPD and 6PPD-quinone, where 6PPD-quinone concentrations in urban stormwater runoff and receiving waters exceeded the 11 nanograms per liter EPA acute aquatic life screening value. The episodic nature of the runoff events emphasizes the importance of best practices for 6PPD-quinone sampling and analyses.