In every activity of metallic carpentry or any other activity that needs welding, the presence of flammable gases is necessary. The most used are acetylene and propane and other gases with a different commercial name containing additives for a better performance.

GASES INVOLVED

Acetylene (C2H2): in bottles; used as fuel for oxyacetylene blowpipes.
Propane (C3H8): in bottles; used as fuel for welding.

EXPECTED RISKS

C2H2: at ordinary temperature and pressure it is a colourless, extremely flammable gas. It bursts very easily, therefore it I often diluted in acetone. Since it bursts and burns very easily, and its explosion releases a great amount of energy, acetylene needs to be handled with the utmost care.
C3H8: used as a fuel, LPG is a mixture of propane and butane, which is often odorized by ethantiol to make its detection easier in case of leaks. It can easily form an atmosphere with high risk of explosion.