Abstract: On January 14, 1988, two employees were near a feed house making general equipment checks. A Carter Day dust collector, which was attached to a Champion 125-hp hammer mill, blew its explosion door outward, forcing ignited grain dust into the grain leg. The ignited grain dust continued up and out into the grain storage bins through a drag auger, causing the steel bin tops to blow off. The metal roof and side walls blew out. The two employees heard a small explosion before a ball of flames shot toward the ceiling, fueled by a second explosion. However, no employees were injured. Subsequent inspection of the tramp metal magnets found them to be clogged with excess metal contaminants. It appears that tramp metal slid by the magnets into the hammers, resulting in sparks that landed in grain dust. The 20-hp, 4000-cfm fan blower spread the sparks and dust through a 12-inch-diameter pipe and into the Carter Day dust collector. The ideal air concentration to support a grain dust explosion was present, combined with sparks and dust. A second explosion was supported and ignited by the first explosion when excess grain collected in the dust collector. The tremendous heat caused rapid expansion that blew the wall and ceiling panels outward.