OMAHA, Neb. — At least 10 people have been hospitalized and others could be trapped today after an explosion and partial building collapse at an Omaha animal feed processing plant.

Interim Omaha Fire Chief Bernie Kanger said he’s not sure how many workers could be trapped in the wreckage of the International Nutrition plant. The fire that followed the explosion about 10 a.m. has been extinguished, but firefighters gingerly searched the structure, fearing that more debris could rain down.

“It’s very extreme conditions” inside the plant now, Kanger said. “There is significant structural damage inside.”

Kanger declined to comment on possible fatalities. At the time of the blast there were 38 employees at work. One firefighter was among those injured, Kanger said.

Omaha-based International Nutrition declined to comment.

Workers’ family members who gathered outside the plant said they’d received cellphone calls from loved ones inside who told them one or two people may be missing or trapped.

Kanger said he’s requested aid from urban search and rescue experts based in Lincoln, so the search could take several more hours.