Gases used for electric welding of metals normally consist of mixtures of various inert gases in different quantities.
Constituent gases in Irish Oxygen Shielding Mixture
ISO-14175 is the international standard which classifies the gases for welding.
Click here for table of welding gases, the ISO-14175 classification and their components.
These depend on the constituent elements in the mixture. However, most shielding gases are inert.
Shielding gas mixtures for electric welding.
Most inert gases in high enough concentrations may cause asphyxiation and death. For more detail on any hazards associated with a particular welding gas check the relevant Safety Data sheet.