The Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended (CERCLA), 42 U.S.C. 9601 et seq., required that the U.S. Department of the Interior establish rules for determining the natural resource damages resulting from a spill of a hazardous substance, crude oil, or petroleum product. Two options for determining these damages are as follows: (1) utilizing a numerical model to estimate the expected injury given the circumstances and location of the spill, known as type A, and (2) measuring the injury in the field, known as type B. This paper primarily examines the type A model (NRDAM/CME), which was developed by individuals from Applied Science Associates, Inc. (ASA) and the University of Rhode Island and which was utilized to estimate damages resulting from the World Prodigy spill in Narragansett Bay, June 1989. Current improvements to the type A model methodology include allowance for complex geometries and multiple habitats within the spill area as well as the addition of the ability to estimate cost to restore, replace, or mitigate the natural resource injuries. The type A methodology is a powerful and cost-effective tool that may be used to assess damages resulting from oil spills in aquatic environments where the much more costly type B methodology is considered unwarranted or too expensive relative to the size of the spill.
