The Hazard Characteristic Code (HCC) designation for Gas Non-flammable, Oxidizer. Hazard Group & Comments: Meets the definition of a Non-flammable Gas (HCC G3), except is an oxidizer; and (b) Does not meet the definition of Poison Gas (HCC G1) or Flammable Gas (HCC G2); and (c) Requires an Oxidizer label and a Nonflammable Gas label for transportation under 49 CFR