Multiple people injured in explosion at Iowa plant

Multiple people were injured in an explosion at a plant in Iowa on Thursday, hospital officials said, as crews continue to battle a massive blaze in the incident.

No fatalities were reported following the explosion at the facility in Marengo, located about 25 miles southwest of Cedar Rapids, Iowa State Trooper Bob Conrad confirmed to ABC News. All 30 people who were in the building at the time have also been accounted for, he said.

Ten to 15 people were injured in the incident, with most in the "mild to moderate injury category," Dr. Theresa Brennan, chief medical officer for University of Iowa Hospitals & Clinics, told reporters.

Only one of the patients was in what they consider to be the most serious injury category for a mass casualty incident, Brennan said.

Drone footage showed emergency responders battling a large fire with black billowing smoke at the plant, which based on property records is a soybean crushing facility, according to ABC Cedar Rapids affiliate KCRG.

The local sheriff's office advised anyone who had been evacuated due to the fire to go to the Iowa County Transportation building, or otherwise stay indoors.

"A large fire is being fought," the Iowa County Sheriff's Office said on social media. "PLEASE, NO SIGHT SEEING!"

City officials also urged residents to avoid the 800 block of East South Street amid the fire.

Residents in the area reported hearing a loud "boom" Thursday morning.

"I'd seen all the ambulances and stuff going, and the fire trucks, and I'd seen the smoke right away," Sam Murphy told KCRG. "So I went down to the Big G and got some water and stuff for them."

Anthony Schropp told KCRG he was among those in the immediate area of the plant ordered to evacuate. He was working three blocks from the plant at the time.

"It shook our building. We heard the explosion," he told the station. "We thought someone drove into our garage door at the shop."

Trooper Conrad said Thursday evening that the fire is not yet out, but is "down" from where it was. Once the fire is extinguished, the state fire marshal can begin an investigation into the cause.

ABC News' Victoria J. Arancio and Matt Foster contributed to this report.