Gas leak

A gas leak refers to a leak of natural gas or another gaseous product from a pipeline or other containment into any area where the gas should not be present. Because a small leak may gradually build up an explosive concentration of gas, leaks are very dangerous. In addition to causing fire and explosion hazards, leaks can kill vegetation, including large trees, and may release powerful greenhouse gases to the atmosphere. A gas leak refers to a leak of natural gas or another gaseous product from a pipeline or other containment into any area where the gas should not be present. Because a small leak may gradually build up an explosive concentration of gas, leaks are very dangerous. In addition to causing fire and explosion hazards, leaks can kill vegetation, including large trees, and may release powerful greenhouse gases to the atmosphere. Pure natural gas is colorless and odorless, and is composed primarily of methane. Unpleasant scents in the form of traces of mercaptans are usually added, to assist in identifying leaks. This odor may be perceived as rotting eggs, or a faintly unpleasant skunk smell. Persons detecting the odor must evacuate the area and abstain from using open flames or operating electrical equipment, to reduce the risk of fire and explosion. As a result of the Pipeline Safety Improvement Act of 2002 passed in the United States, federal safety standards require companies providing natural gas to conduct safety inspections for gas leaks in homes and other buildings receiving natural gas. The gas company is required to inspect gas meters and inside gas piping from the point of entry into the building to the outlet side of the gas meter for gas leaks. This may require entry into private homes by the natural gas companies to check for hazardous conditions. Gas leaks can damage or kill plants. In addition to leaks from natural gas pipes, methane and other gases migrating from landfill garbage disposal sites can also cause chlorosis and necrosis in grass, weeds, or trees. In some cases, leaking gas may migrate as far as 100 feet (30 m) from the source of the leak to an affected tree. Small animals and birds are more sensitive to toxic gases, including the methane and carbon monoxide present in natural gas. The expression 'canary in a coal mine' derives from the historical practice of using a canary as an animal sentinel to detect toxic naturally occurring coal gas. Methane, the primary constituent of natural gas, is up to 120 times as potent a greenhouse gas as carbon dioxide. Thus, the release of unburned natural gas produces much stronger effects than the carbon dioxide that would have been released if the gas had been burned as intended.