Operations at BP Products North America's (BP, BP.LN) Texas City, Texas, oil refinery returned to normal Tuesday following a brief upset at an unspecified process, according to a filing to Texas environmental regulators. Emissions associated with the event started at around 4:20 a.m. CDT when a compressor tripped and ended about four hours later, the report to the Texas Commission on Environmental Quality said. "Operations stabilized the unit and resumed normal operations," the filing said. The Texas City refinery is BP's largest one in the U.S. with capacity to process 455,790 barrels of oil a day. -By Rose Marton-Vitale, Dow Jones Newswires; 212-415-2146, rose.marton@dowjones.com (END) Dow Jones Newswires June 29, 2010 12:54 ET (16:54 GMT)