Blast at US factory kills two, injures 10

An explosion that brought down part of an animal feed processing plant in Omaha, Nebraska, has left two people dead and 10 others seriously hurt, authorities say.

Omaha Police Lt Darci Tierney said on Monday evening that all 38 of the workers who were in the building at the time had been accounted for.

Officials said two workers died, 10 were hospitalised and seven were hurt but refused treatment. The other 19 workers escaped.

Search-and-rescue experts worked into Monday evening to stabilise the building. It was not immediately clear whether their work would continue into Tuesday.

"We haven't cleared the building yet because of the significant risk to our people," Interim Omaha Fire Chief Bernie Kanger said.

Authorities don't know what caused the blast on Monday morning, but Kanger noted that there were no hazardous chemicals at the plant. International Nutrition makes products that are added to livestock and poultry feed to make them more nutritious.

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 mobile phone 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 at International Nutrition for about four months.

Worker 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 (45 metres)," White said. "I ran far enough to make sure nothing else would keep falling."

Afterward, White said, he could see inside the third floor of the building where at least two co-workers were screaming for help.

The plant sits in an industrial area of Nebraska's largest city. There are no residences nearby and no other buildings were evacuated after the explosion.