OMAHA, Neb. — After a blast caused much of an Omaha manufacturing plant to collapse, some workers found themselves buried in debris and others scrambled for their lives.

Two of the 38 workers who were at the International Nutrition plant on Monday morning died and 10 were hospitalized with significant injuries, authorities said. A firefighter was also sent to the hospital with an injured hand.

Jamar White was one of the more fortunate employees — he was outside watching trucks unload at the time of the explosion. 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.”

Key structural supports failed after the blast, and the second and third floors of the plant collapsed on top of the first floor. The blast knocked out the lights in the building and sent workers fleeing for safety.

Authorities don’t know what caused the blast. Omaha Interim Fire Chief Bernie Kanger said at a news conference Monday night that he couldn’t say for sure there was an explosion, though workers and other witnesses described hearing a blast.

The Occupational Safety and Health Administration will investigate the cause of the accident; Kanger said that could take weeks. He noted there were no hazardous chemicals at the International Nutrition plant, which makes nutritional products that are added to livestock and poultry feed.

Kanger said firefighters were able to rescue five men initially, including one who was cut from the debris. Search-and-rescue experts worked into Monday evening to stabilize the building and remove the body of one victim, 53-year-old Keith Everett of Omaha.

A combination of strong winds, cold temperatures and the dangerous rubble forced rescuers to suspend operations before the second victim could be recovered, Kanger said. That person’s name hasn’t been released.