Risk assessment of the Army's Chemical Stockpile Disposal Program

This paper illustrates the application of probabilistic risk assessment methods to a large-scale, multi-site, multi-activity federal program -- The Army's Chemical Stockpile Disposal Program (CSDP), intended to effect the Congressionally-mandated destruction of the nation's inventory of lethal nerve and blister agents (GB, VX, and mustard (H) in both explosive and bulk configurations. The analysis is based on a data base of nearly 3000 accident scenarios -- a mix of modeled and historical data developed by General Atomics. Consequences are measured by potential fatalities as estimated through application of the Army's D2PC agent plume dispersion model and generic fatality data provided by Oak Ridge National Laboratory. The results are expressed in terms of population-based (societal) and area-based (ecological) risk measures for five CSDP alternatives: continued storage; on-site disposal at the eight current storage locations; and three cases involving rail or air transportation and disposal at regional or national sites. On-site disposal results in the lowest programmatic risk, as measured by expected fatalities. The significance of this result is assessed in terms of estimated uncertainty.