When Hurricane Sandy sent water tearing into Tony Locane’s basement last week, he rushed down the stairs to save what he could — his computer, a few pieces of his artwork — as the water climbed up the walls and up his legs from one foot to two feet, to three and to four. And when he retreated to the safety of higher ground, he noticed something on his skin. His body was covered in a “greasy, oily slick,” Mr. Locane said.

The water that rushed into his basement that night came over the banks of the nearby Gowanus Canal, a narrow waterway that cuts a winding path through a section of South Brooklyn, and which the Environmental Protection Agency considers to be one of the most contaminated bodies of water in the country.

“It’s a Superfund site,” said Christopher Webb, a filmmaker whose office right on the Gowanus banks was thick with sediment and a vicious odor of sewers and gasoline last week. “And it’s in here!”

The Gowanus neighborhood of Brooklyn had many of the aching hallmarks of the storm last week: Homes ravaged by fire, caravans of useless vehicles, family photographs left to dry on every available flat surface. But it fared far better than some, and its residents were grateful.