Natural Gas is a colorless, odorless, and non-toxic gas that primarily consists of Methane and other heavier hydrocarbons like ethane, propane, etc. Other components of Natural Gas can include Nitrogen, Carbon Dioxide, Water, and Hydrogen Sulfide. Natural gas burns readily with air when between its lower flammability limit in air (about 4% concentration in air) and upper flammability limit in air (about 15% concentration in air). When Natural Gas contains a set concentration of Hydrogen Sulfide, it is commonly referred to as "Sour" Natural Gas, while if it is below that set concentration it is commonly referred to as "Sweet" Natural Gas. This concentration varies between states/countries. Hydrogen Sulfide in low concentrations can attack soft materials such as Nitrile Buna Rubber (NBR). Knowing these facts, careful selection of materials of construction for pneumatic actuators is imperative for a safe, stable Natural Gas system.