Nomination Summary for Crumb Rubber Synthetic Turf (N21601)

Nominated Substances: Crumb Rubber

Nomination Date: 11/10/2015

Nominator: California Environmental Protection Agency Office of Environmental Health Hazard Assessment

Rationale: The California Office of Environmental Health Hazard Assessment (OEHHA) is engaged in a study to evaluate the health impacts of crumb rubber synthetic turf on players and by-standers in California. Our study is focused mainly on exposure aspects. However, there are a number of uncertainties regarding the toxicological impacts of exposure to chemicals released from synthetic turf, ones that OEHHA is not able to address with current resources. OEHHA therefore requests the National Toxicology Program (NTP) to conduct toxicological studies to facilitate understanding of the health impacts of chemicals released from synthetic turf. Because exposures are ongoing and involve children, there is an urgent need for information on toxicological effects in the near term: Thus, short-term in vivo and in vitro toxicology studies on crumb rubber could be particularly helpful, especially if the results of any such studies could become available within the next 18 months. Crumb rubber is made from waste tires and is used in the manufacturing of synthetic turf and playground mats. Tires are composed of natural rubber, synthetic polymers, carbon black, metals, and additives that make the material resistant to degradation. Some of these materials are known to pose human health risks. Exposures occur via all routes, as dust and volatile organic compounds (VOCs) released from synthetic rubber are inhaled, crumb rubber particles can be ingested, and a good deal of skin contact occurs during play on synthetic turf fields. Health concerns of using crumb rubber in synthetic turf fields and playground mats have been heightened by several recent national television and newspaper reports suggesting that crumb rubber might have caused cancer in young athletes. Lymphoma and leukemia have been the focus of many reports, but others such as cancer of the brain, testis, and thyroid were also mentioned. As a result of these health concerns, many states and cities have tried to pass laws and ordinances banning the use of crumb rubber in athletic fields. Under a contract with the California Department of Resources Recycling and Recovery, OEHHA is conducting a three-year study evaluating exposure to chemicals that may be released from crumb rubber. The study is focused ·on the potential health impacts on young athletes and children, who are among the most highly exposed. As part of the study, we searched the literature and found over 200 chemicals that may be released from crumb rubber, including, but not limited to metals, VOCs, and polycyclic aromatic hydrocarbons (PAHs). We found many of them have limited toxicity information and have no established toxicity criteria. Given the timeframe for our study, short-term toxicology studies of crumb rubber exposure may be the most informative, especially if they could include endpoints with relevance to hematopoietic cancers. This would address, to a certain extent, the health concerns of chemicals with little or no toxicity data and also potentially the possible synergistic effects of multiple chemical exposures. OEHHA believes information generated from these short-term toxicity studies would provide valuable information to address the public's concerns on the health impacts associated with use of crumb rubber in synthetic turf fields and playground mats.

NTP Principles: not specified