The explosion knocked out the lights in the building and sent workers scrambling for safety.
Nate Lewis said he was on the first floor when he heard the explosion. The building went dark, so the 21-year-old used light from his cellphone to make his way across the production floor and outside.
"I was a production line worker, although I don't know if I want to be that anymore," said Lewis, who's worked there for about four months.
Jamar White said he heard a loud crack and looked up to see the back wall of the building collapsing.
"I ran at least 150 feet," White said. "I ran far enough to make sure nothing else would keep falling."
Afterward, White said, he could see inside the third floor where at least two co-workers were screaming for help.
There appears to be structural damage to the top of the building, which sits in an industrial area just south of Interstate 80, which bisects Nebraska's largest city. There are no residences nearby and the other industrial buildings nearby weren't evacuated after the explosion.
Diane Stout said she'd heard from her husband, a manager on the plant maintenance crew, so she knew he was OK. The workers all know each other well, Stout said, so she was hoping to hear good news about friends there.
White's wife, Sarah White, said she was at home with her four children when her husband called her after the explosion.
"I could hear the panic in his voice," she said. "But he said he was OK." She said he'd been watching trucks unload from outside the building when the blast occurred.
"That's where he works every day. That could have been him," White said.