PLATTSBURGH — Workers are nearing completion of the first phase of an extensive environmental cleanup along the Saranac River in downtown Plattsburgh.

New York State Electric and Gas is overseeing the project to remove contaminated soil near the Saranac Street site, which was formerly the location of a manufactured-gas plant. The area was identified as having high levels of coal tar, a by-product of the process.

“We expect the new substation for the Plattsburgh municipal electric system to be in operation by the end of the year,” said Clayton Ellis, manager of corporate communications for NYSEG.

“At that time, the old substation (on site) will be dismantled, and we will then remove soil from the former substation site and bring in clean fill to restore the property.”

The new substation is located on property that had been cleaned during the early stages of the project in 2002, Ellis noted. It sits several hundred feet away from the Saranac River.

The old substation was much closer to the riverbank.

Meanwhile, workers continue to remove contaminated soils from the property while adding clean fill in other areas where the contamination has already been removed.

“More than 100,000 tons of soil have been removed and thermally treated off site,” Ellis noted. “We have not treated any soil on site.”

Officials hope to have the “landside” cleanup effort completed by next spring before moving on to work in the river itself.

“The next step will be removing sediment that is affected by manufactured-gas by-products from the Saranac River,” Ellis said. “We are working with the New York State Department of Environmental Conservation to develop plans for the work in the river.”

That phase is expected to begin in summer 2009, he said, adding that a lot of the time line depends on weather conditions.

Three specific areas in the river will be excavated. Cleanup will be done behind protective coffer dams designed to keep the work areas dry.

Workers also removed a 21-inch sewer line at the site and replaced it with a 24-inch line.

NYSEG and DEC officials are studying the delta in Cumberland Bay to determine if work needs to be done there as well.

Manufactured-gas plants using coal were common in the Northeast from the early 1800s until after World War II. Tar from the Plattsburgh plant was dumped into a large pit overlooking the river.