EE WAS INJURED WHILE WORKING ON A CONVEYOR. WE WERE ADJUSTING ROLLERS BECAUSE WE HAD JUST PUT A NEW CONVEYOR BELT ON. EE SAW SOME MUD ON THE BOARD ROLLER ON THE TENSIONER & HE REACHED INSIDE THE GUARD TO CLEAN IT & THE BELT GRABBED HIS ARM & PULLED IT BETWEEN THE ROLLER & THE BELT. I HAD JUST TAKEN THE LOCK-0UT OFF SO WE COULD TURN THE BELT ON TO ADJUST ROLLERS.