Risk assessment to support management of a hazardous spill cleanup

A modeling effort was conducted to support management of the cleanup of a hazardous material spill resulting from a rail accident. The model considered transport of the hazardous material through the groundwater system and the human health effects of ingesting contaminated groundwater. The model was implemented as a computer program. Subjective probabilities were assessed to account for uncertainties about model parameters, and Monte Carlo techniques were used to solve the model. The model had significant impact on the management of the spill cleanup and provided a common ground for the cleanup management and government regulators to reach agreement on an acceptable method for concluding the cleanup of the spill.