U.S. President Barack Obama has issued an executive order establishing a bipartisan commission tasked with investigating how to prevent future oil spills, CNN quoted two sources familiar with the announcement as saying yesterday. Obama named former Florida Sen. Bob Graham and former Environmental Protection Agency William K. Reilly as commission co-chairs. The sources said Obama on Saturday will announce the formation of the panel, officially known as the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling. After this weekend's official formation, the commission will have six months to issue a report with recommendations on how to prevent spills from offshore drilling.