2021 U.S. Scrap TIre Workgroup (USSTWG)

Questions about tire materials raise questions about scrap tire markets - 6ppd-quinone Department of Toxic Substances Control - Product – Chemical Profile for Motor Vehicle Tires Containing N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) (continued) • “Some of these uses of tire -derived products and materials may directly lead to 6PPD-quinone releases in the aquatic environment. For instance, tire-derived aggregate can be used as a medium for stormwater treatment (CalRecycle 2016; CalRecycle 2018) and may lead to inadvertent contamination of treated water with 6PPD. Tire-derived materials are often used in outdoor applications that cover large surface areas. As such, these materials are exposed to storms that can leach 6PPD and 6PPDquinone.” • “Approximately half of the California -produced crumb rubber is used for asphalt rubber paving, mainly due to requirements such as those in Assembly Bill (AB) 338 (Levine, Chapter 709, Statutes of 2005), which requires Caltrans to use tire asphalt rubber in at least 35% of its paving projects (CalRecycle 2020b). In addition, in 2019 an estimated 12,701 to 17,237 metric tons of California- produced crumb rubber were used for flooring, roofing, tiles, industrial underground couplings, and traffic safety devices, among other purposes, while an estimated 4,536 to 6,804 metric tons were used as infill in synthetic turf fields (CalRecycle 2020b).” 7