Investigators are looking for the cause of a massive fire that swept through a large central Iowa hog confinement lot. Fire crews from eight rural departments spent at least eight hours battling the blaze yesterday afternoon at Tamco Pork Corporation of Gilman, located about halfway between Marshalltown and Grinnell.

An L-shaped structure was destroyed and at least 600 hogs were killed. One person was treated for smoke inhalation. Firefighters were concerned about keeping the fire from spreading to an LP gas tank that was just filled on Monday.