Offshore drilling and the environment

Great overview from The Week about offshore oil drilling.  Why the current ban exists, and what the new effects might be.  The intro:

"How much oil lies under U.S. coastal waters?
Quite a bit. Geologists generally agree that the waters off America’s east and west coasts, on what is known as the outer continental shelf, hold about 18 billion barrels of oil—enough to satisfy U.S. energy needs for two and a half years. That oil is currently off-limits, though, because of a longstanding federal ban on offshore drilling. Oil drilling is allowed in the western half of the Gulf of Mexico, which holds an estimated 70 billion barrels and where about 4,000 drilling rigs are currently in operation. Oil from the outer continental shelf would provide a small boost in available supplies. But even if the drilling ban were lifted tomorrow, production wouldn’t begin until 2017."

http://www.theweekdaily.com/article/index/88073/3/3/Briefing_Offshore_drilling_and_the_environment