<P> Congress passed the Marine Protection, Research and Sanctuaries Act in 1972, which provided for the establishment of National Marine Sanctuaries, in which certain activities, including oil and gas drilling, are prohibited . To date, 13 sanctuaries with a combined area of 150,000 square miles (390,000 km) have been so designated . </P> <P> In 1982, the US Congress directed that no federal funds be used to lease federal tracts off the coasts of Washington, Oregon, or central and northern California . Over the years Congress added other areas until the prohibited area included all the east and west coasts, and the eastern Gulf of Mexico . Congress repeated the effective ban on offshore drilling in these areas every year until September 2008, when an appropriations bill passed the House and Senate without the ban . </P> <P> In 1990, Congress passed the North Carolina Outer Banks Protection Act, prohibiting leasing and drilling on federal seabed offshore from North Carolina . </P> <P> In 1990, President George H.W. Bush issued an executive moratorium restricting federal offshore leasing to Texas, Louisiana, Mississippi, Alabama, and parts of Alaska . The moratorium banned federal leasing through the year 2000 off the East Coast, West Coast, the eastern Gulf of Mexico (offshore Florida Gulf Coast), and the Northern Aleutian Basin of Alaska . In 1998, President Bill Clinton extended the moratorium through 2012 . In July 2008, President George W. Bush rescinded the executive order . </P>

Where are most of the united states offshore oil rigs located