RISK ANALYSIS FOR NATURALLY OCCURRING ASBESTOS ON U.S. NATIONAL FOREST SYSTEM LANDS

Naturally occurring asbestos (NOA) has been a topic of interest and concern for U.S. Forest Service geologists and managers since the early 1980s. Until the early 2000s, there was little if any direction from regulating agencies as to acceptable risk levels when NOA is present. Within the last few years this has evolved from no threshold levels to a dramatic change in thinking that any sample with more than 0.25% or more NOA is unacceptable for the users of national forests. Agency decision-makers are not risk-averse in managing geologic risks based on recent doctoral research pertaining to the management of large landslides on Forest Service system lands. Therefore we have crafted a process in which NOA is characterized and evaluated for likelihood of occurring, and for subsequent consequences, including vulnerability to NOA-related diseases. This system and method approaches NOA problems with a scale-dependent methodology adopted several years ago by the agency for landslide risk analyses. By taking this measured approach to NOA evaluations and decision-making the agency includes sensitivity towards individual risk thresholds and the protection of the American public and agency personnel from NOA.