O2 tanks on the USS Missiouri

Compressed gas tanks on USN/USCG ships use a standard color scheme to indicate the contents.

Green - Oxygen

Yellow - Acetylene

Red - CO2 for firefighting

Orange - Freon or other refrigerant gases

Gray - Nitrogen or Argon for MIG/TIG welding

 

Thank you

Just for general info, the gas bottles we currently use here at the Navy Yard are stamped with the date of manufacture and the dates of hydro testing. We still have in service, bottles made prior to and during WW II, no lie.