Direct vent fireplaces are fueled by either liquid propane or natural gas. Chemical plants produce olefins by steam cracking of natural gas liquids like ethane and propane. All propane and LP Gas applications require the use of a regulator. The modern lampworker uses a flame of oxygen and propane or natural gas. Gaseous hydrocarbons such as mixtures of pentane, propane, butane and isobutane took their place. They are usually natural gas, propane (LP) or bio ethanol. Electricity, propane, or natural gas are usually used to achieve these temperatures. Another approach is using automatic noise guns powered by propane gas. Detectors are also available that warn of carbon monoxide and/or explosive gas (methane, propane, etc.). It is a mixture of propane and butane. Butane has the same hazards to consider as propane. Liquid propane, which expands into a gas, has also been used. In a similar manner, propane and cyclopropane, butane and cyclobutane, etc. By-products are usually used as fuel for the propane dehydrogenation reaction. The burner has a pilot light to ignite the propane and air mixture.