WINDHAM, Conn. -- A train carrying tankers of ethanol derailed in Windham Thursday morning, according to officials.

Four freight cars were involved in the derailment on a line that runs parallel to Route 203. The train was en route to Providence at the time of the derailment.

The Providence and Worcester freight train was carrying four 30,000-gallon tankers, of which at least one was filled with ethanol. Three of the tankers had overturned, officials said. One of the tankers was partially derailed. Department of Environmental officials said none of the tankers were leaking, but the situation was being monitored.

Fire officials said the tankers somehow disconnected from the engine while heading to Providence from the Midwest.

The chief of the South Windham Fire Department, John Chapman, said the derailment occurred at about 4 a.m., but the town was notified of the situation at about 7:30 a.m.

"The railroad felt no need for fire apparatus because there was no leak at the time. They should have notified offices in town," Chapman said.

P&W spokeswoman Mary Angelis said the company is conducting an internal investigation and declined to comment as to why it took more than three hours to notify local emergency crews of the situation.

Members of the Windham Fire Department were at the scene Thursday morning and hazmat teams were en route.

"I am very worried -- that was the first thing that came on my mind because it has ethanol, but they said no problems, nothing leaking. I guess we'll wait until hazmat gets here," said Robin Edson, who lives near where the train derailed.

Officials said uprighting the train would likely take two days and involve cranes and specialized equipment.

Officials said the overturned train did not pose an apparent threat to anyone in the area and that no commuter lines were affected.