[whazor]

There are natural gas leaks on a regular basis here in Europe. It only explodes with a fire source. People smell the gas leak and inform the fire station.

[lstodd]

Only if it's doped. Pure methane is odorless.

[whoooooo123]

Is it ever not doped though? At what point in the process do they put the smell in?

[tblt]

At the distribution point, usually. Some gas networks intended for industrial use don't contain the chemical that makes gas smell as that gas is an input in a chemical process, not burnt for heat.