An explosion injured eight people Friday morning at a soybean processing plant in the Port Neal Industrial Complex, about 20 miles south of Sioux City.
Police and fire crews from several communities were on the scene at Ag Processing Inc., battling a blaze that started after the explosion, said Gary Brown, Woodbury County emergency management coordinator.
"There is a small fire on the second floor of the plant," Brown said.
The plant makes soybean oil and soybean meal. Brown said it was shut down for routine cleaning and maintenance when the explosion occurred.
The eight injured were taken to Mercy Medical Center in Sioux City, said Dr. Larry Sellers, chief medical officer.
Five of them were in critical condition, Sellers said.
"Three are stable, actually in good condition and will probably be able to leave the hospital today," Sellers said. "Most of the severe injuries are related to burns and inhalation of hot material, burning both internally and externally."
The explosion, which occurred just before 9 a.m., involved hexane gas, Brown said.
Hexane is a highly flammable chemical used to extract vegetable oils from crops such as soybeans.
Jim Rodenburg, a spokesman at Ag Processing headquarters in Omaha, Neb., said the company was investigating an incident at its plant at the Port Neal complex, but he could not elaborate.
The company, which employees about 1,600, is the third largest supplier of refined vegetable oil in the United States, said spokesman John Campbell.
AG Processing has six plants in Iowa and one each in Nebraska, Missouri and Minnesota.
The Port Neal plant has about 50 full-time employees, Campbell said.
Also at the Port Neal complex is a Terra Industries Inc. fertilizer plant, where a 1994 explosion killed four people, injured 18 and released a toxic cloud of ammonia.