NEW ORLEANS, Louisiana (CNN) -- The owner of the barge that spilled about 420,000 gallons of industrial fuel in the Mississippi River near New Orleans said Thursday the company was not to blame for the accident, but said it will be responsible for the cleanup.
Fuel oil surrounds plants on the banks of the Mississippi River after the collision.
Paul Book, vice president of operations facilities for American Commercial Lines Inc., said divers were assessing the barge as it lay against a bridge pier.
"We have reports of oil that is bubbling, coming from the bow and the stern compartments," he said at a news conference attended by several government officials.
V-shaped booms containing skimmers have been placed below each compartment to collect and siphon off the oil, he said. The operation will be done twice. Watch scenes from the oil spill »
"We have high hopes that that will stop the release ... coming from the barge," Book said.
The spill, which affected 98 miles of one of the nation's busiest waterways, resulted from a collision early Wednesday between the 61-foot barge carrying the fuel and a tanker. The two collided just north of the massive bridges connecting downtown New Orleans to communities across the river. See a map of where the spill happened »
The tug Mel Oliver, which had been hired to push the barge upriver, had no properly licensed crew on board, Coast Guard officials said. The tugboat pilot had only an apprentice mate's license instead of the required master's license.
The oil was being hauled from John W. Stone Oil Distributor in Gretna, said Coast Guard Petty Officer Jaclyn Young.
Two investigations are under way -- one by the Coast Guard and the other by the National Transportation Safety Board.
Book and Coast Guard Capt. Lincoln Stroh, the port captain in New Orleans, declined to respond to reporters' questions about how an unqualified pilot was hired.
"American Commercial Line has stepped forward as being responsible for the spill cleanup, not responsible for the incident," Stroh said. "The investigation will clearly establish fault at a later date, but that's not a place to go right now."
Book added, "We were not the operator of the towing vessel nor the operator of the ship."
At least 100 ships were stalled Thursday along the river from just south of New Orleans to the Gulf of Mexico, the Coast Guard said.
He said a marine transportation recovery unit will prioritize the ships according to the urgency of their cargo so they can be moved either above the oil spill zone or to the east or west.
Coast Guard Lt. j.g. Anastacia Visneski said, "It's going to take us several days before we can get the river open, and it's going to take weeks before we can clean it all up.
"Right now, our priority is for the safety of the people in the parishes surrounding the river, the safety of the environment, and containing and cleaning up the spill as quickly as possible."
Containment booms have been installed to prevent the oil from spreading to environmentally sensitive areas and seeping into water-supply intake valves in Gretna, St. Bernard, Dalcour, Belle Chasse, Pointe a la Hache, Port Sulphur and Boothville-Venice, Young said.
Tom MacKenzie of the U.S. Fish and Wildlife Service said there have been few reports so far of oil-covered wildlife, but much of the shoreline hasn't yet been searched.
Plaquemines Parish, which is 100 miles long, shut off its water intake valves after the spill, and was banned from using the ferry to New Orleans, except for emergencies. Parish President Billy Nungesser said he is prepared to truck water in if necessary.
"We're running low on the east bank of Plaquemines. We thought we'd run out today," he said late Thursday afternoon. He said the parish was still testing the level of contamination.
"We will not turn on the outtakes until we are 100 percent sure it is safe to drink," he said. "The whole Mississippi has a sheen on it."
The east bank has 1,500 residents, a coal depot, an oil storage facility and other commercial businesses, he said.
The west bank of Plaquemines Parish, population 22,000, was using water from Jefferson Parish, whose supply valves are north of the spill, Nungesser said.
In southern Plaquemines, Boothville-Venice has ponds that can provide a 20-day water supply, he added.
Book said 50,000 feet of boom has been deployed in the river cleaning, with another 50,000 still available. At least 350 people are involved in the cleanup, he said.
The oil was being skimmed and sucked into vacuum trucks, then put in temporary storage tanks. He estimated that 140 barrels of oil -- not quite 6,000 gallons -- had been contained.
The 590-foot Liberian-flagged tanker Tintomara was not damaged in the collision, but the crash split the barge nearly in half. A swifter-than-normal current quickly drew the slick downstream.
Stroh said the oil, widely used as marine fuel, is heavier than diesel but lighter than crude.
The spill is much smaller than the ones that followed Hurricane Katrina in 2005, when the Coast Guard estimated that more than 7 million gallons of oil were dumped into the Mississippi and nearby waterways.
The Mississippi is the major shipping route from the Midwest to the Gulf of Mexico, and New Orleans is among the largest U.S. ports.