TEXAS CITY, Texas -- A barge that once carried some 900,000 gallons of heavy tarlike oil was cleared Sunday of its remaining contents, a day after the vessel collided with a ship in the busy Houston Ship Channel and leaked as much as about one-fifth of its cargo into the waterway.
Coast Guard officials said that up to 168,000 gallons were dumped after one of the barge's tanks ruptured and that oil had been detected 12 miles offshore in the Gulf of Mexico as of Sunday afternoon.
"This is a significant spill," Capt. Brian Penoyer, commander of the Coast Guard at Houston-Galveston, said.
But he said the emptying of the barge Sunday, a process known as lightering as contents are transferred to other vessels, was an important step as it had eliminated the risk of additional oil spilling.
The channel, one of the world's busiest waterways for moving petrochemicals, was shut for a second day Sunday. As many as 60 vessels were backed up both trying to get out and get in.
More than 380 people -- "and we've ordered more," Capt. Penoyer said -- plus a fleet of oil-retrieving skimmers and other vessels deploying some 60,000 feet of containment booms around environmentally sensitive areas worked to mitigate the damage.
The area is home to popular bird habitats, especially during the approaching migratory shorebird season.
Officials said they had scattered reports of wildlife damage but no specifics. Some black tarlike globs, along with a dark line of a sticky, oily substance, could be detected along the shoreline of the Texas City dike, a 5-mile-long jetty that juts into Galveston Bay across from a tip of Galveston Island.
"That is the consistency of what the cargo looks like," Jim Guidry, executive vice president of Houston-based Kirby Inland Marine Corp., the nation's largest inland barge company and owner of the barge, said when the substance was described to him at a news conference. "We're very concerned. We're focused on cleaning up."
He said the company was taking responsibility for the costs.
The barge has been moved to a shipyard and is no longer at the scene of the spill, according to a statement Sunday evening from Texas Gov. Rick Perry's office.
Capt. Penoyer said at least one cruise ship, initially socked in by fog Saturday, was being allowed to end its trip and return to Galveston. He said others would be handled on a case-by-case basis. The cruise ship's path into Galveston would take it through a safety zone defining the oil cleanup area.
There was no timetable for a total reopening of the channel, which typically handles as many as 80 vessels daily.
The Coast Guard and National Transportation Safety Board were investigating what happened.
"It will take quite a bit of time, given the complexity of the vessels and a very busy waterway," Capt. Penoyer said.
The contents of the torn tank, equal to about 4,000 barrels, were lost or displaced into other vacant areas of the barge. Capt. Penoyer said currents, tides and wind were scattering the spill.
"Containment was never a possibility in this case," he said.
Jim Ritterbusch, president of energy consultancy Jim Ritterbusch and Associates in Chicago, said if the bottleneck of vessels in the Gulf eased in a day or so, there likely wouldn't be much impact on fuel prices. A more prolonged backup could push up prices briefly, he suggested.
Also closed was the Texas City dike, a popular fishing spot that goes out into the Gulf for a few miles.
The spill site is 700 yards offshore from the Texas City dike. A crane and several small boats could be seen at the cleanup site, and dozens of trucks were at a staging area along the beach.
The captain of the 585-foot ship, Summer Wind, reported the spill Saturday afternoon. Six crew members from the tow vessel, which was going from Texas City to Port Bolivar, Texas, were injured, the Coast Guard said.