This publication recommends hazard ratings for most of the compressed gases found in CGA C-7, Guide to Classification and Labeling of Compressed Gases, in accordance with the National Fire Protection Association (NFPA) hazard identification system [1, 2]. This publication aids in standardizing compressed and liquefied gas classifications as designated under the NFPA hazard identification system. For a comparison between NFPA 704, Standard System for the Identification of the Hazards of Materials for Emergency Response, and labels under U.S. Occupational Safety and Health Association’s (OSHA) Hazard Communication Standard, see OSHA’s Quick Card 3678-08 2013 [2, 3, 4].