EE WAS REMOVING AN ACETYLENE & OXYGEN BOTTLE FROM A SERVICE TRUCK FOR USE AT A CLOSER LOCATION. AFTER RELEASING THE MOUNTING BRACKET, EE PROCEDED IN REMOVING THE ACETYLENE TANK. WHILE HOLDING THE TOP OF THE ACETYLENE TANK ON THE GROUND THE OXYGEN CYLINDER, (CAPPED), FELL TOWARD EE APPROX 4 FT PINNING THE PALM OF HIS HAND BETWEEN THE PROTECTIVE RING OF THE ACETYLENE CYLINDER & THE O