A barge filled with more than 1 million gallons of hot liquid asphalt ran aground Monday morning, leaking its load into the James River, officials said.

It was not immediately known how much of the substance spilled into the river, said Lt. Gary Hutchison of the Henrico County Fire Department.

The barge was carrying more than 1 million gallons of the cargo when it ran aground about 4:30 a.m. about five miles south of Richmond. One tank, holding 120,000 gallons of the 270-degree asphalt, was damaged, causing the leak, Hutchison said.

The other tanks on board did not appear to be leaking, the Coast Guard said.

County officials called in the Coast Guard, the Virginia Department of Emergency Management and the Environmental Protection Agency to help, Hutchison said.

The barge, owned by Vane Line Bunkering of Baltimore, Md., was being pushed by a tug boat operated by Dann Marine of Chesapeake City, Md., Hutchison said.

The Coast Guard was investigating what caused the barge to run aground, Hutchison said.