EE WAS UNLOADING A RAILCAR AT THE PLANT, HAMMERING ON A HOPPER TO IMPROVE PRODUCT FLOW. HE HEARDA SOUND CHANGE IN THE CAR'S AIRLINE THAT INDICATED LESS AIRFLOW AND HIGHER PRESSURE. AT THAT INS TANCE THE AIRLINE CONNECTOR SUPPLYING UNLOADING AIR BLEW OFF THE CAR & HIT HIS ARM. ONE OF THE 2METAL STRAPS THAT TIE THE HOSE TO THE CONNECTOR HAD 9"" OF LOOSE EXCESS.