Three workers were unaccounted for after an explosion Tuesday at a Raleigh-area food plant, officials said.
The explosion, reported about 11:30 a.m., caused sections of the roof to collapse at the ConAgra Foods plant in Garner, North Carolina, police spokesman Joe Binns said at press conference.
Rescuers were looking inside the plant for three workers who were missing, Binns said. At least 20 people were transported to area hospitals, he said. No fatalities were immediately reported.
"There was no warnings, no signs," Garner Mayor Ronnie Williams said. "It all happened very abruptly."
The incident was "not totally contained," Binns said. A small fire continued to burn at the plant.
The cause of the blast was unclear, Binns said.
Video from the scene showed holes in sections of the roof of the 50,000-square-foot plant. First responders set up a makeshift triage area near the building. A section of the roof was collapsed, and pipes could be seen spewing liquid believed to be ammonia. Watch liquid spew from building »
ConAgra Foods is a leading food company whose brands include Healthy Choice, Chef Boyardee and Orville Redenbacher. The Garner plant is known for producing Slim Jim beef jerky products.
The company was working with authorities to ensure that employees "are getting all of the support that they need," ConAgra Director of Corporate Communication Stephanie Childs said. "The employees' health is their only real concern at this time."
Leonard Spruill, a worker at the plant, told WRAL-TV he heard a loud explosion and several of his co-workers were badly burned. Spruill told the station he suffered burns on his head, arms and legs and had to have his clothes cut off of him.