SOUTH SIOUX CITY, NEB. — One person is hospitalized after an explosion ripped a gaping hole in a grain elevator owned by Anderson Farms Inc. on May 29 in South Sioux City.

South Sioux City Police Chief Ed Mahon told the Sioux City Journal that three employees were on site when the explosion occurred. One was transported to Mercy Medical Center in Sioux City with serious injuries. He was later transported to a hospital in Lincoln, Neb.

A second person sustained slight injuries but was not hospitalized, and a third was uninjured, the newspaper said.

Mr. Mahon said the cause of the explosion has not been determined.

The police department said structural engineers have deemed the building unstable in its current state. Immediately following the incident, law enforcement took steps to block the surrounding streets and evacuate nearby homes because of the uncertainty regarding the structural integrity of the building.