What Does Natural Gas Mean?
Natural gas is a naturally occurring mixture of various hydrocarbon compounds, consisting primarily of methane, ethane, and other substances that belong to a group of hydrocarbons known as paraffins.
Natural gas is a fossil fuel energy source, like coal and oil, which means that it was formed from the remains of plants, animals, and microorganisms that lived millions of years ago.
Safeopedia Explains Natural Gas
When considered from the perspective of the energy industry, natural gas is divided into two categories: conventional and unconventional. Conventional natural gases are considered easy to extract, while unconventional gas is more difficult to access. Some types of natural gas deposits that were once considered unconventional have become conventional as new technology has made them easier (and cheaper) to access.
Both conventional and unconventional gases are extracted commercially. Natural gas is a relatively clean-burning type of fossil fuel, which means that it does not produce significant air pollution or carbon dioxide. However, the extraction of many types of unconventional gas requires methods such as fracking, which are themselves energy intensive and associated with a significant environmental cost.
Natural Gas Composition
As a mixture of multiple substances, natural gas does not have a single consistent composition associated with it - that is, different sites have gas of different compositions. Enbridge, an energy firm, states that its natural gas is composed of 87%–98% methane, 1.5%–9.0% ethane, and also contains a variety of other hydrocarbon and non-hydrocarbon (e.g., nitrogen) substances in smaller amounts.
In addition to containing many substances that are useful for creating heat, natural gas is often contaminated with various pollutant substances, such as sulfur. The amount of pollutants varies depending on the source from which the gas is being extracted.
Natural Gas Safety
The natural gas industry is a safety-sensitive industry. The extraction, processing, and transportation of natural gas all involve significant safety hazards. Due to its environmental impact, natural gas extraction and processing activities are also subject to environmental health and safety (EHS) regulations.
Some jurisdictions also regulate natural gas–related safety issues through a governmental energy agency, such as the Alberta Energy Regulator. Furthermore, transportation-focused agencies are often responsible for regulating the safety of natural gas transport through pipelines. In the U.S., the Department of Transportation's Pipeline and Hazardous Materials Safety Administration (PHMSA) is responsible for this task.
Both OHS and EHS activities are concerned with preventing leaks of natural gas from occurring at any point in the extraction, processing, and transport pipeline. Natural gas leaks in enclosed spaces can displace oxygen, leading to suffocation. As natural gas is odorless, it can be difficult to detect leaks when they occur.
Exposure to hydrogen sulfide (H2S) - a toxic and undesired compound commonly found within natural gas reserves - is another significant natural gas hazard. Natural gas with high amounts of H2S is also known as sour gas. Sour gas is purified (or “sweetened”) before it reaches consumers; however, workers face a risk of serious harm or death if they are not provided with adequate safety precautions at any time before or during the sweetening process. In 2015, for instance, a Canadian man died of H2S poisoning while conducting testing at a sour natural gas well.
Natural gas is also combustible, and facilities that handle natural gas typically conduct a number of activities that can pose fire or explosion hazards if adequate precautions are not taken. This is one of the chief occupational hazards associated with the natural gas industry. OSHA’s list of accidents that contain the keyword “Natural Gas” is primarily composed of incidents in which workers were injured or killed by fires or explosions.