HORNICK, Iowa (AP) – The Iowa Department of Natural Resources is monitoring the cleanup after a fertilizer fire at a co-op in Hornick in western Iowa.  The fire at the Western Iowa Cooperative broke out Tuesday. The Woodbury County sheriff’s office urged residents to evacuate because of concerns about air quality and residents’ safety.  The DNR says a small dam built by firefighters prevented water runoff contaminated with fertilizer and herbicide from reaching a ditch, which drains into the west fork of the Little Sioux River.   The dam and additional sand barriers also prevented runoff for storms that hit Tuesday night.  Officials say the fire was caused by a malfunctioning loader.  No one was injured. The DNR doesn’t plan to take any enforcement actions.