SafetyIda challenges continue: damaged drillship, disputed oil slick, and 94% of US Gulf output still shut inNoble, Enterprise Offshore facing disputes involving their vesselsPossible oil spill: Aircraft have been dispatched to investigate reports of a miles-long slick in the Gulf of Mexico south of Port Fourchon, LouisianaPhoto: NOAA/AP/SCANPIXMark PasswatersHouston