Turning the Corner on Hazardous Tire Compounds: A Management Framework for Tire Additive Pollution

Abstract

Vehicle tires are complex chemical formulations that abrade during use, releasing tire particles everywhere roadways exist. The recent discovery that the tire additive transformation product 6PPD-quinone (N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone) was primarily responsible for mortality in sentinel fish species has prompted regulatory and scientific scrutiny of tire additives as contaminants subject to widespread human and ecological exposure. Tire additives pose a global pollution challenge to human and ecosystem health due to their high emissions via tire wear particles combined with loss from in-use and waste tire materials. Such releases often occur in close proximity to humans, and mobilized material or chemicals are easily transported to habitats where adverse effects are possible. This issue demands a commensurate policy response that remains unaddressed by existing pollution management policies. We here propose five principles for managing tire additives: mandating nonhazardous alternatives and their transformation products, acknowledging impacts throughout tire life cycles, transparency in tire compositions, characterizing effects, and international harmonization. Following these principles, we outline a Management Framework for Tire Additive Pollution (MF-TAP) that recommends a phased regulatory approach, data transparency, independent expert panels, and internationally coordinated governance to drive the development and use of alternative, nonhazardous tire additive compounds. Managing tire additives according to the MF-TAP will allow us to better address the pollution potential of hazardous tire additives and reduce their impacts on human health and ecosystems.