Starting Tuesday, U.S. regulators will hold regular meetings on oil and natural gas pipeline safety standards. A series of pipeline issues, ranging from a deadly gas pipeline explosion in California, to a massive oil spill in Michigan, have brought pipeline safety to the forefront of the American energy debate. The safety meetings, scheduled in Virginia, come days after environmental regulators in Nebraska end a public comment period for Keystone-XL, one of the most contentious U.S. pipeline issues. The U.S. Pipeline and Hazardous Materials Safety Administration scheduled hearings beginning Dec. 11 in Virginia. During those meetings, safety committees are expected to…