Defines "a substance other than convention oil" for purposes of the Intervention on the High Seas Act as meaning those oils, noxious substances, liquified gases, and radioactive substances enumerated in the Protocol Relating to Intervention on the High Seas in Cases of Marine Pollution by Substances Other than Oil or otherwise determined by the Secretary of the Department in which the Coast Guard is operating as being liable to create a hazard. States that for purposes of implementing the Act, in determining whether there is grave and imminent danger of major harmful consequences to the coast line or related interests of the United States, the Secretary shall consider the interests directly affected or threatened, including but not limited to human health, fish, shellfish, and other living marine resources, wildlife, coastal zone and estuarine activities, and public and private shorelines and beaches.