In this photo taken Wednesday, May 26, 2010, Patient Andrew Vega buys bags of medical marijuana at the Coffeeshop Blue Sky dispensary in Oakland, Calif. After becoming the first U.S. city to impose a special tax on retail medical marijuana sales, Oakland soon could become the first to sanction and tax commercial pot cultivation, an activity that remains illegal under federal law. Two City Council members are preparing legislation, expected to be introduced next month, that would create at least three industrial scale growing operations. (AP Photo/Jeff Chiu)