PITTSBURGH (KDKA) — A barge incident is under investigation.

A tow boat was pushing tow empty barges when they become loose and went adrift down the Ohio River.

The barges then struck a petroleum barge that was in a fleet area, knocking it loose and it too traveled down the river, reaching marker 1.

There are no signs of oil in the river.

The Coast Guard is investigating what caused the barges to become loose.

Stay with KDKA for the latest details.