In 1981 the US congress adopted a moratorium against drilling on the US outer continental shelf covering 5 km to 320 km offshore. The US EIA estimates that 18 billion barrels of oil are in the area covered by the moratorium which could be enough to match current US production for 10 years. However, a 2007 analysis by the agency concluded that opening up drilling in the moratorium area would not have a significant impact on domestic crude oil and natural gas production or prices before 2030. The primary concern about offshore drilling has been that unsightly oil rigs would damage tourism or that spills would threaten the environment. In July 2008 President Bush decided to remove the moratorium and permit drilling offshore