More than a dozen people were injured Friday when a nitrogen line ruptured at the Beechcraft aircraft manufacturing facility in Wichita, Kansas, authorities said. The explosion caused part of the building to collapse.
Investigators are still trying to determine what caused the explosion, CBS Wichita affiliate KWCH reported. Crews are searching the structure and checking the distribution system for a secondary rupture.
Daniel Wegner, deputy fire chief for Sedgwick County, said the explosion happened at around 8 a.m. at the facility, which is in the eastern part of the city.
Wegner said the explosion happened when a 3-inch liquid nitrogen line ruptured. The rupture was contained, but gas continued to vent, although it posed no risk to nearby residents, officials said.
John Gallagher, the county's emergency medical services director, said 11 people were taken to hospitals and four were treated at the scene. No one was killed, but one person has potentially serious injuries, he said. The plant was closed for the holiday, so only a limited number of people were there at the time, according to KWCH.
Worker Robert Baker said he was inside the building when the explosion occurred but was on the opposite side of the facility. He told The Wichita Eagle that he saw the walls flex.
"There was dust and debris, even from the other side," said Baker, 36, who has worked at the plant for about a month. "Dirt in the air permeating through the walls coming down the hallways and stuff like that."
He added: "That was the most scared I've ever been in my whole life, and I'm not easily rattled. But when the walls start flexing and it sounds like the roof is about to cave in, I get pretty panicked and scared."
Joel Schepis, who lives in a neighborhood west of the Beechcraft plant, said the the explosion rattled his house and dust and debris fell through cracks in his ceiling.
"If you've ever been to an airshow, it sounded like a sonic boom," he said.
The explosion was felt nearly 2.5 miles to the northwest, The Eagle reported.
Roz Hutchinson, a spokeswoman for the Ascension Via Christi health system, said nine people were taken to its St. Francis hospital in Wichita. She said one was in critical condition, three were in serious condition and four others who were treated either had been released or were expected to be soon. She said the ninth patient was still being assessed.
Stephanie Harder, a spokeswoman for Beechcraft's parent company, Textron Aviation, said that the company has accounted for all of the workers and visitors who were at the plant at the time of the explosion.
The explosion comes at a difficult time for the aircraft industry in Wichita, which is a major sector of the Kansas economy.
Boeing recently announced that it would helping to pay workers at Spirit AeroSystems, which produces the jet's fuselages. And earlier this month, Textron Aviation announced that it would lay off an unspecified number of workers, most of them in Wichita.in January, forcing the state to consider
Harder said the structure where the explosion happened is part of a complex of buildings and houses the business' composite manufacturing and experimental aircraft.
"Difficult day. Difficult news," she said.
The federal Occupational Safety and Health Administration is at the plant, said Sedgwick County Sheriff Jeff Easter. The state Fire Marshal's Office and the local lodge of the International Association of Machinists and Aerospace Workers didn't immediately respond to phone messages.