PARIS – The Environmental Protection Agency has announced the completion of its work at the sludge lagoons of the former A.C. Lawrence Leather Co. on Oxford Street.

The project was initially estimated to cost $1.3 million, but the overall cost for the yearlong project was $4 million.

The increase came after site coordinator AmyJean McKeown increased the initial estimate of the amount of waste that needed to be removed from 10,000 tons to 40,000 tons.

The seven-acre site is next to the Little Androscoggin River and over a sand and gravel aquifer in a 100-year flood plain.

Pollution from chromium deposits was first noted by a resident in 2000, and the initial survey of the site was conducted in 2002 and 2003 by the Maine Department of Environmental Protection.

It returned in 2006 to map the site and do a contamination investigation.

Levels of chromium in the soil on the riverbank edge ranged from 23 parts per million to 48,000 parts per million, with most areas reading higher than 5,000 parts per million.

The chromium sludge on the riverbank was 10 to 15 feet deep, and also deposited in 12 lagoons on site.

The sludge also contained lead levels of up to 780 parts per million and diesel range volatile organic compounds at levels of up to 17,300 parts per million, according to the EPA. Organic compounds were found in the river, and levels of chromium from 24 to 200 parts per million were found in river sediments.

Chromium is not harmful if ingested in small amounts, but may lead to health problems or death if too much is consumed.

The A.C. Lawrence Co. stood on the opposite bank of the river beside Pine Street and deposited waste at the site from an indeterminate time prior to 1952 until 1973-1974, when the company began using the town’s treatment facilities. The tannery closed in 1985.

The town has waived foreclosure on the property since the closure, and so has not been in possession of the property.

If voters choose to foreclose on the property, the town will own the site.

McKeown said while walking the site with the Board of Selectmen in August that the EPA removed 33,000 tons of waste between Aug. 14, 2006, and July 6, 2007.

According to a memo from December 2006, the EPA had excavated 13,888 tons of waste from nine of the lagoons, exceeding an initial estimate of 10,000 tons on site. McKeown also recommended putting in temporary sheet piling at the site to prevent the river from eroding the riverbank and releasing more contaminants.

After the waste was removed from the site, the lagoons were filled with backfill. The site is now covered by a layer of topsoil and grass.