Is it safe?

It's gas. Natural gas.  Truly natural gas.  Not the fossil fuel that is named to fool us.  It doesn't contribute to global warming, if that's what you are worried about.  But it is gas.  It is flammable.  It burns. You can hurt yourself, sure.  Singe your eyebrows, that kind of thing.  Treat it the way you would treat the gas from any gas oven.