U.S. Coast Guard units operating in the Houston - Galveston area of responsibility have as of 4 p.m. Tuesday processed 51 reports of pollution and repaired or replaced 40 percent of critical aids to navigation damaged or missing in the wake of Hurricane Ike.Of the 51 pollution reports, 15 incidents require active cleanup, 14 require passive action and 22 require no further action by the Coast Guard. The reports cover a range of incidents including the discharge of petroleum products from storage tanks that have been damaged and/or are submerged in flood waters, the discharge of fuel from submerged machinery and sunken or damaged vessels in marinas, and natural gas leaks. A pipeline in , leaking natural gas from a valve currently under six feet of water.