It’s caked in clay, but looks solid enough as the backhoe gently hoists Joan Fitzgerald’s 500-gallon fuel oil tank out of the ground and into the air and deposits it on her front lawn in Clifton. But back in the excavated hole, dark residue stains the dirt and the odor of petroleum is heavy above the pit. "I can smell it," she said. Environmental consultant Steve Rich chops at the clay. Underneath holes appear in the 66-year-old steel. Daylight shines through some that are as big as dimes. "I think, unfortunately, quite a bit of oil might have come out,"...