ABSTRACT The Committee on Marine Transportation of Heavy Oils was formed by the National Research Council's Marine Board, in response to a congressional mandate that requested the U.S. Coast Guard to assess the risk of spills of oil, which may sink or be negatively buoyant, and the ability to clean them up. The study was also to assess clean-up technologies and identify and appraise technological and financial barriers that may prevent the prompt response to such discharges. The specific objectives of the study were to: (1) assess the threats posed by the marine transportation of group V oils by characterizing the trade in such oils and, in general terms, the resources at risk; (2) assess the adequacy of cleanup technologies for spills of group V oils and recommend research needs to develop new technology, as appropriate; and (3) identify barriers to effective response and recommend technological, financial, or management measures that would prompt effective response to spills of group V oils. This paper ...