New Jersey’s Oyster Creek Nuclear Generating Station remains under an official Alert, a day-and-a-half after the US Nuclear Regulatory Commission declared the emergency classification due to flooding triggered by Hurricane Sandy. An Alert is the second category on the NRC’s four-point emergency scale. Neil Sheehan, a spokesman for the federal regulator, said that floodwaters around the plant’s water intake structure had receded to 5.7 feet at 2:15 PM EDT Tuesday, down from a high of 7.4 feet reached just after midnight.