INJURED EE & CO-WORKER WERE USING THE VACUUM TRUCK TO CLEAN THE RAW MILL. A LARGE STONE WAS STUCK IN THE END OF THE 4"" HOSE. HE TRIED TO DISLODGE THE STONE WITH HIS RIGHT HAND. THE STONE MOVED & THE SUCTION PULLED HIS ARM INTO THE HOSE UP TO HIS ARMPIT, CAUSING A CONTUSION.