NTP Research Report on Synthetic Turf/Recycled Tire Crumb Rubber: Feasibility Study in Support of Non-inhalation In Vivo Exposures of Synthetic Turf/Recycled Tire Crumb Rubber

Abstract

Public health concern for playing on synthetic turf fields with crumb rubber infill has increased in recent years. Crumb rubber manufactured from recycled automobile tires contains potential carcinogenic and toxic substances, and, with over 12,000 synthetic turf fields in the United States, the potential for exposure is widespread. The National Toxicology Program (NTP) conducted research to improve the understanding of potential human exposure to crumb rubber and its biological activity. The objective of the studies as described in this report was to evaluate likely exposure scenarios in humans that could be translated into exposure routes for in vivo testing. Feasibility trials, without animals, were conducted to evaluate various crumb rubber formulations for bedding (incidental contact), feed (indirect ingestion), oral gavage (direct consumption), and dermal (direct contact) exposures.