HINTON, Iowa (AP) – An Iowa construction company has been sued over an explosion of natural gas that followed a pipeline rupture in northwest Iowa. The lawsuit was filed by the pipeline owner, Northern Natural Gas Co, of Omaha, Neb., against DeRocher Construction, of Le Mars.  Two DeRocher workers were injured by the blast that sent a fireball hundreds of feet into the air on April 25. Authorities say the men were operating trenching equipment that struck the pipeline near Hinton.

The lawsuit was filed Wednesday in U.S. District Court in Sioux City. It says Northern Natural Gas spent nearly $440,000 for emergency response, inspection and repair and other expenses to get the pipeline back into operation. DeRocher Construction has declined to comment.