CHICAGO, Dec. 27 (Xinhua) -- Sludge was flowing into the Kankakee River from the site of an explosion that destroyed a building earlier Monday at a water treatment plant in Kankakee, about 60 miles south of Chicago, local officials said.

No one was hurt and all 13 people who work on the property are accounted for, according to Chicago Tribune.

But one to one and a half million gallons of the substance was flowing into the river from the plant, said Kankakee Fire Department.

The department said officials were able to stop the flow of the sludge and that an 8 million-gallon reservoir tank was used in the process.

The explosion occurred a little before 9 a.m. at a building that produces methane gas used for energy, the department said. The water treatment part of the plant was still operational, though.

The explosion sent debris into the surrounding neighborhood. The treatment plant serves several communities besides Kankakee, but there were no reports of any households experiencing problems as a result of the explosion.

The cause of the explosion was being investigated.