Energy regulators in North Dakota and other states "have done an awfully good job" in overseeing hydraulic fracturing and other natural-gas drilling operations on federal lands, said Harold Hamm, chairman and CEO of Continental Resources. The federal government should leave the task of regulating the industry to the states, Hamm said. "The geology differs state by state," he said. "The conditions differ state by state. Most of the rules we're involved with from a regulatory aspect have been adopted from the early producing states -- Oklahoma, Texas."