Ten to 15 people were injured in the explosion and fire that hit an alternative fuel plant in Marengo, Iowa, a town southwest of Cedar Rapids and 80 miles east of Des Moines.
A reported 30 workers were inside the plant when the explosion occurred. The cause is under investigation.
It happened at an operation by a company called C6-Zero which reportedly recycles discard asphalt shingles. The site is owned by Heartland Crush, a soybean mill.
The Des Moines Register reported that officials at the scene described it as a “biofuel” plant.