Amendment extended provisions of the Clean Air Act to oil and gas platforms located on the Outer Continental Shelf (OCS) along the Pacific, Arctic, Atlantic, and eastern gulf coasts and to the vessels that service them. It required sources within 25 miles of the seaward State boundary to meet the same regulations as those for similar onshore sources and sources in State waters. It required the EPA to monitor and complete a study of the sources of atmospheric deposition of toxics in coastal waters, their tendency to bioaccumulate, and their effects on human life.