On a recent rainy February afternoon, Peter Sacripanti, partner-in-charge of McDermott Will & Emery’s New York office, climbed into an aluminum trailer parked on the remains of an oil refinery in Greenpoint, Brooklyn. The trailer sits across the road from the East Coast’s biggest sewage treatment plant and atop the nation’s largest known standing pool of oil. Weeks earlier, the New York attorney general had announced the latest in a long string of lawsuits over the toxins. But Sacripanti, looking relaxed in an apple-green sweater, was hardly perturbed by his noxious surroundings.

As Exxon Mobil Corp.’s defender, Sacripanti had come to this compound of storage tanks and treatment systems, far from his well-appointed Madison Avenue office, to make a point about the oil. Sure, he admits, Exxon Mobil and its predecessors leaked or dumped millions of gallons of petroleum in Greenpoint in decades past. But things were different then. And Exxon Mobil isn’t liable for any damages now.