NEW YORK (CNN) -- The Environmental Protection Agency announced Thursday that it won't start dredging the Hudson River until 2008, yet another delay in the project to remove harmful PCB's from the river's bottom.

The decision to delay dredging came after the EPA reviewed and agreed with a General Electric work plan from March that showed a necessary riverside sediment processing facility could not be constructed in time for the 2007 dredging season.

New York Gov. George Pataki 'extremely disappointed' in EPA's decision to delay dredging of the Hudson River.

"We have independently verified the accuracy of the projected construction schedule provided by GE and, after careful review, must agree that its timeline for the delivery of key pieces of equipment needed for the sediment dewatering ... is accurate," EPA regional administrator Alan Steinberg said in a statement.

The dredging is aimed at removing PCBs dumped legally into the river from GE plants in Hudson Falls and Fort Edwards from 1947 to 1977 before PCB use was banned.

Gov. George Pataki expressed his frustration regarding the EPA's decision to delay the project.

"I am extremely disappointed in the EPA's surprising decision to allow yet another delay. I urge the EPA the refocus and redouble its efforts to get this important project under way as soon as possible," Pataki said.

While the EPA insists that it made a "Herculean effort" to move the project along as quickly as possible, the decision to further delay the start date did not come as a shock to environmental groups who accuse GE of consistently stalling.

"Its not surprising, but disconcerting because GE continues to drag its feet and now it's dragging the EPA with it," said Rich Schiafo, environment project manager for Scenic Hudson. "You don't wonder when it's going to happen anymore, but wonder if it's ever going to happen."

A spokesman for GE could not be reached for comment.

The EPA decided in 2002 to dredge 2.65 million cubic yards of sediment - enough dirt to fill an area the size of 10 football fields to a height of 145 feet - which is expected to cost GE about $460 million.

The company has vigorously opposed the plan in the past, insisting that the dredging itself will present an environmental threat by stirring up PCBs in the water.

PCBs are dense, highly toxic chemicals, used as coolants in heavy electrical equipment that experts say may stay toxic for as long as 250 years.

From CNN's Deborah Brunswick

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