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,
Natural gas prices flows based on underlying index prices or delivery obligations or time periods. Participants use these tools to further hedge their financial exposure to the underlying price of natural gas. The demand for natural gas is mainly driven by the following factors: Weather conditions can significantly affect natural gas demand and supply. Cold temperatures in the winter increase the demand for space heating with natural gas in commercial and residential buildings. Natural gas demand usually peaks during the coldest months of the year (December–February) and is lowest during the "shoulder" months (May–June and September–October). During the warmest summer months (July–August), demand