BOLTON — The state Department of Environmental Conservation is investigating allegations that officials in the town of Bolton have filed falsified monthly reports that measure contaminants discharged from the public wastewater system.

A person familiar with the matter said criminal charges are being considered against a town official who was allegedly aware that the Warren County municipality had a history of using chemicals to manipulate the phosphate and nitrate levels at the town sewer plant before they were recorded in monthly discharge monitoring reports filed with state.

Town Supervisor Ronald Conover said last week that he was unaware of a criminal probe involving the DEC or a town official.

Thomas French II, the superintendent of the town's water and sewer departments, on Monday said no one from DEC's law enforcement division had interviewed him "as of late."

"I don't wish to make any comments about anything without representation," said French, 37, who has worked for the town since 2004 and became head of the water and sewer departments in the past few years.

The state has penalized the town of Bolton in the past for wastewater discharges of nitrates and phosphorous that exceeded regulations, records show.

Antiquated municipal sewer systems along Lake George, which is a public drinking water source, have posed environmental problems for decades. Last year, the state announced a $4.2 million grant to help build a $18 million sewage treatment plant in Lake George.

Nitrates feed algae blooms that have plagued the 32-mile-long lake for decades. Since 1980, algae levels in the lake, particularly in its southern portion around the village of Lake George, have been steadily increasing, reducing the clarity of the water.

The town of Bolton's sewer treatment plant is located off Brook Street and serves nearly 500 residences.