You can't eat them, because they are fossil fuels and products of petroleum industry, and they contain a lot of hydrocarbons and alkane gases, which can easily lead to cancer or food poisoning when they enter food. Therefore, when barbecue with liquefied gas, the food should be separated from the flame with iron plates.

Upstairs you should know that lighter gas and candles are a mixture, not pure things. The main component of lighter gas is butane, and there are many other things.