NEW ORLEANS (AP) — The Coast Guard says a petroleum-based product leaked from a storage tank area in southwestern Mississippi and moved through a canal into the Mississippi River, where it formed a miles-long sheen.

The sheen was spotted Wednesday and was largely dissipated by Thursday morning. However, Coast Guard Lt. Jonathan Mangum said some of the material had gathered at scattered spots along the river banks in Mississippi and Louisiana. Coast Guard officials said two companies have been hired to respond to the leak. The Coast Guard was working with Louisiana authorities, including officials in Point Coupee and West Feliciana parishes, to assess and address any environmental effects.

The Coast Guard identified the responsible party as El Toro Production Co. of Natchez. The company did not return a telephone call for comment.