EXPOSURE TO NATURALLY OCCURRING ASBESTOS DUE TO OFF-ROAD VEHICLE USE

Off-road vehicles (ORVs) are a very popular outdoor recreational activity. ORVs are designed to operate in rugged, unpaved terrain and they produce extensive amounts of fugitive dust. ORV use in regions that contain naturally occurring asbestos (NOA) or erionite (NOE) can produce dust that may put ORV participants at risk for potentially hazardous inhalation exposures. A review of existing literature regarding recreational activities and mineral fiber exposure was conducted. Additionally, the potential public health impact of ORV use in 5 western states (AZ, CA, CO, NV, and UT) was estimated by calculating the proximity of known mineral fiber occurrences to areas of ORV use. Our review criteria found 15 publications on this topic, most were from the Environmental Protection Agency (USEPA) and Agency for Toxic Substances and Disease Registry (ATSDR). The range of personal exposures reported varied from a maximum of 5.6 f/cc (PCM) to concentrations lower than 0.01 f/cc (PCMe). Increased exposures were found with increasing vehicle speed, and closer proximities to other vehicles or the road. Multiple studies also indicate that children may experience higher exposures to mineral fibers as compared to adult ORV riders. In the 5 states examined, 665 known occurrences of NOA/NOE were reported, of these approximately 80% are located within 20 miles of an ORV trail, and nearly a third were located within 1 mile. Individuals who operate ORVs in areas where NOA/NOE is a component of the underlying soil or trail may experience elevated exposures to mineral fibers. Given the prevalence of ORV trails in close proximity to currently known NOA/NOE, epidemiologic and surveillance studies are recommended. Public health initiatives should concentrate on increasing awareness of these risks so that ORV users can make informed choices and take appropriate measures to limit these risks when possible.