As Hurricane Sandy roars into the mid-Atlantic with heavy rains and high sustained winds, a national chemical disaster site is threatening to overflow into residential neighborhoods.

The Gowanus Canal in Brooklyn, New York is lined by multiple residential communities before it flows into New York Harbor. The canal has been in service since 1869 and over the years has been a transportation route for gas plants, mills, tanneries and chemical plants.The EPA placed the Gowanus Canal on the Superfund list of America’s most contaminated sites in 2010. The water includes high levels of PCBs, coal tar wastes, heavy metals and toxic organics. The water in the canal has been called a “threat” to nearby residents who might want to use the canal for recreation or fishing.

The storm surge has already caused the Canal to overflow its banks. Water has started to flow into multiple residential areas and several small business sites. Police have been stationed throughout the evacuation area to make sure no one trespasses into the toxic water.

There are concerns, after the flood waters recede, of the chemicals and materials that will remain on the ground and inside buildings which could render buildings and streets unsafe for habitation.