Natural gas tens of millions of structures that use the fuel, the individual risk of using natural gas is very low. Natural gas heating systems may cause carbon monoxide poisoning if unvented or poorly vented. In 2011, natural gas furnaces, space heaters, water heaters and stoves were blamed for 11 carbon monoxide deaths in the US. Another 22 deaths were attributed to appliances running on liquified petroleum gas, and 17 deaths on gas of unspecified type. Improvements in natural gas furnace designs have greatly reduced CO poisoning concerns. Detectors are also available that warn of carbon monoxide and/or explosive gas (methane, propane,
Billion cubic metres of natural gas Billion cubic metres of natural gas Billion cubic metres of natural gas (abbreviated: bcm) is a measure of natural gas production and trade. Depending of implied standards, this measure may represent different value of energy content. According to the standard defined by the International Energy Agency, it corresponds in average to of energy in the case of Russian natural gas and of energy in the case of Qatar's natural gas. According to the standard defined by the International Energy Agency, the gas physical volume is used, which is measured at the temperature of at atmospheric pressure. According to the Russian