The 315-mile-long Hudson River, which flows in the eastern part of New York state from high in the Adirondack Mountains down to the Battery in New York Harbor, has always been a pivotal waterway in the U.S.—for business and pleasure.

Polychlorinated biphenyls (PCBs), a group of 209 chemicals that have very good thermal and electrical insulating properties, were widely used in industrial applications for decades beginning in 1929, when they were first commercially produced under the Aroclor trade name.