An employee was preparing to sandblast a tank while standing on a scaffold. The employee put his hood over his head and realized that the breathing air was not turned on. As he took off the helmet and set it to the side, the sandblaster activated and started whipping through the air. He tried to catch the hose and was hit by the blast media, knocking him off the scaffold. He sustained a broken nose, laceration of the right eye, and had abrasive media injected into his right cheek.