VICKSBURG, Miss. – Experts say the stretch of Mississippi River where vessel traffic was halted after a barge hit a railroad bridge on Sunday is one of the most dangerous along the 2,500 mile-long river.

Late Monday, cleanup crews were skimming oily water near Vicksburg, a day after a barge struck a bridge, rupturing a compartment holding 80,000 gallons of oil.

Authorities said the oil was being contained and there was no evidence of it washing ashore downriver.

Oil was being pumped from the ruptured tank into another tank on the same barge. Officials hope to eventually transfer all the oil to another barge.

Tugs were holding the barge at the bank on the Louisiana side of the river, directly across from Vicksburg’s Riverwalk and Lady Luck casinos.

Coast Guard spokesman Lt. Ryan Gomez said a tug was pushing two tank barges when the collision occurred about 1:30 a.m. Sunday. Both barges were damaged, but only one leaked. Authorities declared the bridge safe after an inspection.

Officials did not yet have an estimate of how much oil had been pumped out, or how much spilled into the Mississippi.

Authorities said an environmental disaster was unlikely as the swift current dispersed the oil. They were less certain when the river would reopen to vessels.

On Monday, 31 tugboats, barges and other vessels were parked waiting for the river to reopen, said Army Corps spokesman Kavanaugh Breazeale. The river was closed to traffic for eight miles north and eight miles south of Vicksburg.

Ann McCullough, spokeswoman for American Waterways Operators, a trade association for the U.S. towboat and barge industry, said the shutdown is concerning. But she couldn’t estimate the daily economic impact. “It’s a significant matter when the nation’s waterborne superhighway is disrupted for any reason,” she said.