CORINNA – The monumental cleanup of Corinna’s downtown Superfund site, which began in 1997, has been so successful that less aggressive changes to future cleanup activities are being proposed.

“The bottom line is that the cleanup is working, and the groundwater contamination is not expanding and has receded,” U.S. Environmental Protection Agency Project Manager Ed Hathaway told a small group of town residents Thursday night.

Wearing a broad smile, Hathaway, who has been with the project for seven years, called the Corinna cleanup a model of success.

“Already, 22 of the 25 contaminated acres are cleaned and ready for development,” he said. “And the concentration within the [contamination] plume no longer threatens the Sebasticook River.”

Through the removal of 100 tons of contaminated soil and the injection of nearly 50,000 gallons of chemicals directly into the contaminated bedrock, the size of the area of contamination has shrunk by half, like downsizing from a pond to a puddle.

Without the treatments already conducted, the pockets of contamination in the bedrock would have taken nature 150 to 600 years to cure. Hathaway said Thursday, however, that the groundwater should be completely restored in as few as 80 years.

Corinna’s 25-acre downtown was declared a Superfund site after contamination in local wells was discovered in 1983. The laundry list of carcinogenic chemicals found in wells, the Sebasticook River, bedrock and the surrounding soil was determined to have come from the dyeing and manufacturing process at Eastland Woolen Mill, which began operation in 1909.

The mammoth mill, which dominated Corinna’s downtown area, was removed along with 54,673 pounds of hazardous substances found inside, 600 tons of soil were treated each day, the river was moved along with Route 7, and a complicated flushing program to inject chemicals into the bedrock began.

During the initial planning stage, the EPA estimated the project would take 18 months, cost $10 million and require removing 22,000 cubic yards of soil. Once the project got under way, however, the contamination proved much more extensive.

The budget was revised to $50 million with a completion date of December 2006. The excavation and treatment of the soil were completed ahead of the original projection, however, allowing site redevelopment to occur ahead of schedule.

“Ninety percent of the land that was originally in cleanup is now available for development,” Hathaway said.

Thursday’s meeting was part informational hearing and part public hearing, meeting legal requirements of the EPA. Residents had few questions, and the Maine Department of Environmental Protection applauded the changes.

Hathaway and Andy Boeckeler, project manager of Nobis Engineering of New Hampshire, explained that the plan’s amendments include eliminating long-term groundwater extraction as well as a flushing technology that would further diminish the size of the contaminant plume in bedrock below the former Eastland Woolen Mill.

The trade-off will be time. If the plan had been implemented, total water cleanup could have been accomplished within the next 60 years, Hathaway said. Without it, it will take 80 years. The bonus, he said, is that by eliminating the complicated treatment, the state and federal environmental agencies involved will save $20 million.

“But this is not about the money,” Hathaway asserted. “This is based in science. The savings are just a benefit.”

Boeckeler explained that EPA and DEP officials will remain on site through 2008, conducting soils and water analysis and installing monitor wells. Removing Corinna from the Superfund list could happen as early as this year, Boeckeler said.