Hudson Cleanup 5 Things: A final PCB dredging season launches along the upper river

General Electric Co. is set to begin its sixth and final season of dredging the upper-Hudson River on Thursday as part of an estimated $2 billion Superfund project. Here are five things to know about the massive cleanup of poly-chlorinated biphenyls, or PCBs.

TO BE DREDGED

Crews this year are targeting 250,000 cubic yards of contaminated sediment. Dredged sediment is barged to a nearby facility where it is pressed dry and shipped out by train to a burial site. Dredge crews will be working in some challenging areas this year near dams and along shallow stretches near islands.

GREAT EXPECTATIONS

Environmental Protection Agency regional administrator Judith Enck said Thursday that "this is an important year in the history of the Hudson River." The EPA is on target to reach its overall goal of removing enough contaminated sediment to significantly reduce the amount of PCBs floating downriver and contaminating fish.

HOW IT HAPPENED

Before 1977, GE discharged into the river about 1.3 million pounds of PCBs, which were used as coolants in electrical equipment. A 200-mile stretch of river down to New York City was listed as a Superfund site in 1984, though a cleanup was delayed amid opposition from GE and some residents. GE dropped public opposition after the EPA signed a dredging order in 2002. The cleanup began in 2009.

WHAT HAPPENS AFTER THIS YEAR

Flood plain work, habitat reconstruction along the river and long-term monitoring will continue after dredging is finished. Also, federal Natural Resources Trustees will assess the harm done to the river's resources. That could lead to a settlement with GE over its liability or to litigation.

SOME WANT MORE

Environmentalists have repeatedly called for GE to expand dredging beyond the boundaries set by the EPA's order in 2002 to make sure the river is thoroughly cleaned. There also have been calls for GE to perform navigational dredging of the Champlain Canal along the river. The Fairfield, Connecticut-based company has shown no intention of doing that, stressing that "100 percent" of the PCBs targeted by the EPA will be addressed. Realistically, any agreement to expand dredging would need to be struck this year, before the treatment facility is decommissioned.