Six barges broke loose Monday near Greenville, Miss. when the 122’9”x38’x12' towboat Big J.O. struck the bank of the Mississippi River at mile marker 501.6.

Four of the barges were empty, the Coast Guard said, and two were loaded with urea ammonium nitrate. The agency said one of the loaded barges was sinking, while four others had been secured.

Big J.O. is owned by Yazoo River Towing, Vicksburg, Miss. 

The river was closed from mile marker 503 to mile marker 490 following the incident. The Coast Guard is investigating.