One of the two barges towed by the tug Nature's Way Endeavor leaked oil into the river after striking the Vicksburg Railroad bridge Sunday in Mississippi, the Coast Guard said in a release.
No injuries were reported.
The source of the leak was contained and tank levels were being monitored, the Coast Guard said.
Coast Guard Marine Safety Unit in Vicksburg has dispatched a pollution response team to assess the size of the spill and oversee cleanup operations.
While the actual amount of the spill hadn't been determined, the leaking tank held about 80,000 gallons of light crude oil, the Coast Guard said.