Fire departments from throughout Jefferson and Dodge counties responded today to a call at 7:20 a.m. for what firefighters said may have been a dust explosion at Insight FS cooperative grain mill in Ixonia that injured one worker. According to Jefferson County Sheriff's Department Chief Deputy Jeff Parker, who accompanied the Daily Times on a half-block walk west to the mill on Marietta Avenue from a command post set up at the intersection of Marietta and American streets, word among fire fighters was that the incident may have had its origins in a dust explosion at the grain facility. The incident seemed to be under control at 8:50 a.m. today. Parker said one of the three full-time and two office workers employed at the mill had opened the plant early today following the long, Labor Day holiday weekend and had been caught in the explosion. That worker was treated and transported for his injuries to Aurora Hospital at Oconomowoc and his condition was not known.