A case study of tire crumb use on playgrounds: Risk analysis and communication when major clinical knowledge gaps exist

Physicians and public health professionals working with the U.S. Environmental Protection Agency's Region 8 Pediatric Environmental Health Specialty Unit (PEHSU) received several telephone calls requesting information regarding the safety of recycled tire crumb as a playground surface constituent placed below children's play structures. There were no reported symptoms or adverse health effects in exposed children. The literature available on the safety and risk of exposure to crumb rubber constituents was limited and revealed no information quantifying exposures associated with product use. Callers were informed by the PEHSU that no evidence existed suggesting harm from intended use of the product, but gaps in knowledge about the product were identified and communicated. Here the case of crumb rubber on playgrounds is used as a model to present an approach to similar environmental medicine questions. From defining the question, to surveying traditional and nontraditional resources for information, synthesis of findings, and risk communication, the case provides a model to approach similar questions.