These are organic substances in a gaseous aggregate state, which belong to the groups of alkanes and belong to the 2nd class of hazardous goods. They are part of natural gas, are released during the separation of petroleum gas or as an adjunct product of various chemical reactions. Pure propane does not smell and has no color, so to determine the presence of this gas, third-party odorous substances are added to it. Butane, in turn, has a distinctive smell, contact with which can lead to asphyxia and heart problems. Both gases are highly explosive. In the chemical industry, propane is required in the manufacture of polypropylene and solvent. Propane and butane in their properties are similar to other types of hydrocarbon fuels and therefore it is used as fuel for internal combustion engines, welding or heating systems, or as household gas.

The most common mixture of propane-butane is technical (M P B T) in approximately the same ratio.

It is sold in a liquefied aggregate state and belongs to dangerous transportation. For the sake of maintaining this form, propane transportation must be carried out at a pressure of the order of 16 atm. in accordance with the rules for the transport of dangerous goods. Transportation of propane in cylinders is carried out as usual transportation of cylinders, which are covered with scarlet paint with the corresponding sign. Upon contact with air, it forms an explosive mixture of gases that ignites when the space is saturated with propane more than 2 percent. It follows that the transportation of propane and oxygen in the same vehicle is strictly prohibited.

According to ADR, there are exceptions that define the maximum amount of gas in a transport unit, the delivery of which is not considered the transport of dangerous goods. Transportation of propane cylinders is not considered dangerous if the vehicle contains no more than 15 pieces of 50 liter cylinders (21 kg of propane). Delivery of propane butane in liquefied form is possible in isothermal tanks called gas carriers.