Emergency crews worked through the night to cap off the broken ends of a natural-gas pipeline that exploded 10 miles north of Moab Thursday morning.
By Friday, a small fire was still burning and one end of the broken line had been sealed. Work had also begun on the remaining open end, which crews hoped to have sealed by afternoon, said Diane Allen, a National Parks Service ranger who was manning the phones at an operations command post set up at the site.The cause of the accident was still undetermined Thursday night. However, investigators had determined that an existing pipe ruptured, not a new pipeline that is under construction, as initially believed.
U-191, closed after flames shot across the highway and melted the asphalt, was not expected to reopen until sometime late Friday. Passenger car traffic was being re-routed to back roads, and commercial truck traffic was prohibited.
"We've got a bunch of truckers stuck in Moab," Allen said.
Thursday's 9:50 a.m. blast injured four pipeline workers and sent emergency response crews from law enforcement and medical facilities into overdrive as they anticipated a worst-case-scenario number of injuries.
Three workers suffered minor injuries and were treated and released at Moab's Allen Memorial Hospital. Another worker suffered internal injuries that required surgery, but he was listed in good condition Friday, hospital public relations coordinator Clinda Lasiter said.
The accident also forced the evacua- tion of visitors to Arches National Park, about one-half mile south of the accident site. The park will remain closed until the road is re-opened, Allen said.
Allen was working at the park visitor center Thursday and heard the explosion.
"I could see flames up above the rocks. I'd be just guessing, but I think the flames were 100 feet high or more," she said.
Workers at the scene told police they heard a loud hissing noise and began to run away from the pipeline. One witness said he saw the fire, which was slowly moving up the line, and knew an explosion would follow.
Investigators for Williams, the Tulsa-based parent company of Mid-America Pipeline Co., which owns the pipeline, were still working to determine the cause of the rupture late Thursday.
"There was a rupture of the line and a fire, but we don't know yet what caused it," said Glenda Sylvia, spokeswoman for Williams, which is also the parent company of the former Northwest Pipeline Co., based in the University of Utah Research Park.
The new pipeline is being installed adjacent to an existing pipe that carries a variety of natural gas liquids or NGLs, which include ethane, propane, butane and natural gasoline. It wasn't yet known which NGL was moving through the pipe at the time of the incident, Sylvia said.
The existing line, consisting of 10-inch and 12-inch pipe constructed in 1982, is the line that ruptured. The escaping liquids, which turn to gas when they hit the air, were then somehow ignited, Sylvia said.
Construction of the new pipeline began in August and will run from Daggett County in northeast Utah to a point near Bloomfield, N.M.
The new line, a combination of 10-inch, 12-inch and 16-inch pipe, was originally expected to be operational by Jan. 1, but that date had been pushed back to mid-year even before the accident.
The new pipe will expand the capacity of the current line from 75,000 barrels of NGLs per day to 125,000 barrels per day.
Williams is expanding the pipeline because, over the past few years, gas processing plants in the Rocky Mountain region have increased production thanks to new discoveries of oil and gas and greater demand for oil and gas liquids nationwide.