Reuters: A U.S. regulator on Monday allowed Exxon Mobil Corp to restart operations on the Texas leg of its Pegasus pipeline, which spilled thousands of barrels of oil into a residential area in Arkansas last year. The Pipeline and Hazardous Materials Safety Administration (PHMSA) approved Exxon's restart plan for a 210-mile (338-km) stretch of the pipeline from Corsicana to Nederland at 80 percent of the operating pressure in place before the March 29, 2013 incident in the small town of Mayflower, Arkansas....