The California Stormwater Quality Association (CASQA) has petitioned the Department of Toxic Substances Control to list tires containing zinc as a Priority Product pursuant to the Department's Safer Consumer Products program (SCP). The CASQA petition argues that zinc from the tires abrades from vehicle travel and enters state waterways via stormwater runoff where it has a significant adverse impact on aquatic organisms.
The DTSC SCP regulations allow interested parties to file petitions seeking to add or remove chemicals to the program's Candidate Chemicals list or to add a or remove a chemical-product combination from the Priority Products list. The petition process has been used only once before. In 2016 the Center for Environmental Health petitioned the Department to add cans lined with bisphenol-A (BPA) to the Priority Products list. DTSC denied that petition.
CASQA is made up of stormwater management organizations and interested individuals, including cities, counties, special districts, and consultants. The organization's petition seeks to add tires containing zinc to the Department’s list of priority products. In its petition, CASQA notes that numerous state waterways have been listed as "impaired" for zinc due to the impact of the chemical on aquatic organisms and that most of that zinc has been sourced to the runoff from roadways. CASQA admits that there is no evidence that exposure to runoff zinc causes a significant adverse impact on human health. However, DTSC in its latest Priority Products Workplan states that it will emphasize the need to protect state waters in its selection of chemical-product combinations to identify as Priority Products. In fact, the Department has recently selected laundry detergents containing nonylphenol ethoxylates (NPEs) as a potential addition to the Priority Products list [see DTSC Considering Listing NPE Containing Laundry Detergents as Priority Product , May 28, 2018].
The SCP regulations require the Department in evaluating a petition to add a Priority Product to consider the same factors that it uses in selecting products on its own. The CASQA petition includes a discussion of each of these factors, including the function of zinc in tires, a list of manufacturers and importers of tires who might be adversely impacted by a listing, adverse impacts from zinc in tires, exposure to humans and aquatic organisms, and other factors specified in the regulations, including the availability of safer alternatives. Zinc is added to tires to improve the vulcanization process. CASQA notes that in conversations it had with tire manufacturers and importers in preparing this petition, the industry argued that zinc oxide is essential for the vulcanization process and that alternatives do not currently exist. CASQA cites several articles published by the industry and others that have investigated alternatives.
DTSC will now evaluate the petition. The regulations require the Department to act on the petition no later than the next change to the Priority Products list.