Actually, modern industrial kitchens have almost stopped using liquid fuels, but methane or, to a smaller extent, liquid petroleum gas (LPG).

GASES INVOLVED

Methane CH4: during the whole operation life of a kitchen, both when operating or standstill, gas leaks may occur because of mechanical stops of the gas pipes that deliver gas to burners. Such leaks create explosive concentrations.
LPG (C3H8): during the whole operation life of a kitchen, both when operating or standstill, gas leaks may occur because of mechanical stops of the gas pipes that deliver LPG to burners. Such leaks create explosive concentrations.

EXPECTED RISKS

CH4: methane is a simple hydrocarbon and is in nature in form of gas. Methane is the main component of natural gas and is an excellent fuel, able to form easily in atmosphere resulting in a high risk of explosion.