Barrel (unit) continued to use the same size barrels. In the worldwide oil industry, an oil barrel is defined as 42 US gallons, which is about litres or 35 imperial gallons. Oil companies that are listed on American stock exchanges typically report their production in terms of volume and use the units of bbl, Mbbl (one thousand barrels), or MMbbl (one million barrels) and occasionally for widest comprehensive statistics the Gbbl (or sometimes Gbl) denoting a billion. There is a conflict concerning the units for oil barrels (see ). For all other physical quantities, according to the International System of Units, the
Barrel (unit) of oil, chemicals, and other products are transported in steel drums. In the United States, these commonly have a capacity of and are referred to as such. They are called 210-litre or 200-kg drums outside the United States. In the United Kingdom and its former dependencies, a drum is used, even though all those countries now officially use the metric system and the drums are filled to 200 litres. Thus, the 42-US-gallon oil barrel is a unit of measure, and is no longer a physical container used to transport crude oil, as most petroleum is moved in pipelines or oil