The National Environmental Policy Act (NEPA) of 1969 requires federal agencies to examine the direct, indirect, and cumulative, or additive, environmental effects of their activities. An EIS is a detailed public document that provides an assessment of the potential effects a federal action may have on the human, natural, or cultural environment.
An OEIS is prepared to comply with U.S. Executive Order 12114, Environmental Effects Abroad of Major Federal Actions, of 1979. The Executive Order requires federal agencies to consider the potential effects of their actions on the environment outside U.S. territorial waters. U.S. territorial waters extend 12 nautical miles from shore.