These can include butane and propane, that are present in gas canisters used for camping stoves and gasoline barbecues. https://4gameforum.com/redirect/?to=aHR0cHM6Ly9mcmVlYmVzdGFkcy5jb20vMTgyL3Bvc3RzLzkvODAvMTY2OTkyOC5odG1s