PITTSFIELD -- A North Adams municipal employee is facing criminal charges related to an October 2012 diesel spill in which fuel leaked into the Hoosic River.

Glenn A. Robert, 63, of North Adams, pleaded not guilty on Monday in Berkshire Superior Court to three charges: violation of the notification requirement of a release or threat of release of oil or hazardous waste, illegal disposal of hazardous waste, and discharging a pollutant into the waters of the commonwealth.

He was released on his own recognizance by Judge Daniel A. Ford and is expected back in court in July for a pretrial hearing.

Robert's attorney, Richard D. LeBlanc, told The Eagle that he had just received Robert's case and was unable to comment.

The spill that led to the charges, filed by the Massachusetts Department of Environmental Protection, occurred at about 7:30 a.m. on Oct. 15, 2012, at the North Adams Department of Public Works facility on Ashland Street.

According to DEP documents, Robert left a fuel pump unattended and about 20 gallons of diesel spilled onto the ground after the pump slipped out of the city vehicle that was being refueled. The fuel went into a storm drain and made its way into the nearby Hoosic River.

On Tuesday, Mayor Richard J. Alcombright told The Eagle that after the spill, the city's DPW supervisor was notified, as was the fire department and the DEP.

"A containment boom was used [in the Hoosic River] by the fire department," said the mayor.

A Springfield-based company issued a report on behalf of the city after the incident stated that residents near the river smelled diesel fuel and contacted the fire department, which in turn contacted the DEP. By law, a spill of this type must be reported within two hours, which the DEP alleges wasn't done in this case.

The spill was made worse when Robert sprayed water on the fuel in an attempt to remove it from the ground near the pump, according to the report.

"The fuel pump operator did not realize that the application of water to the fuel spill would exacerbate release conditions," the report states.

The report found that a heavy rain on the night of the spill and into the next morning helped dilute any fuel left in the river, that the fire department's actions also helped, and that the released fuel did not pose a public safety risk.

"[We] would expect that any petroleum remaining in the environment after deployment and recovery of the absorbents would rapidly diminish within a matter of days," the report stated. The spill has "been found to pose no significant risk of harm to human health, safety, public welfare, and the environment."

Alcombright said Robert is still employed by the city. The mayor didn't want to comment on anything related to the pending litigation.

He said the city has, and continues to, educate its employees on environmental issues.

The state DEP referred all questions to the Berkshire District Attorney's Office, which refused to answer any questions related to the case.