What Is CNG?


Compressed natural gas (CNG) is a readily available alternative to gasoline that’s made by compressing natural gas to less than 1% of its volume at standard atmospheric pressure. Consisting mostly of methane, CNG is odorless, colorless and tasteless. It’s drawn from domestically drilled gas wells or in conjunction with crude oil production.

Natural gas powers more than 12 million vehicles on the road today. Unfortunately, only 110,000 of these are being used today in the U.S. The average growth rate in the U.S. shows a 3.7% per year since 2000, as contrasted with a booming global growth rate of 30.6% per year. Expanding the numbers of CNG fueling stations would allow for the increase of CNG vehicles on U.S. roads. There are 12,000 around the world, yet the U.S. claims about 1,100. More stations will continue to be built in America in the coming years.

However, as gasoline prices continue to rise, American interest in CNG is rising accordingly. And with good reason – CNG costs about 50% less than gasoline, it emits up to 90% fewer emissions than gasoline,* there’s an abundant supply and it’s produced right here in America. So it’s affordable, clean, abundant and American.

*Emissions reductions may vary by pollutant and make/model of vehicle.


Although compressed natural gas is flammable, it has a narrow flammability range, according to the U.S. Environmental Protection Agency, making it an inherently safe fuel. Strict safety standards make CNG vehicles as safe as gasoline-powered vehicles. In the event of a spill or accidental release, CNG poses no threat to land or water, as it is nontoxic. CNG also disperses rapidly, minimizing ignition risk relative to gasoline. Natural gas is lighter than air and will not pool as a liquid or vapor on the ground. Nevertheless, leaks indoors may form a flammable mixture in the vicinity of an ignition source.

CNG is primarily methane, which is a greenhouse gas that could contribute to global climate change if leaked. Methane is slightly soluble in water and under certain anaerobic conditions does not biodegrade. If excess amounts accumulate, the gas can bubble from water, possibly creating a risk of fire or explosion.

Reported incidents of bus fires are related to engine failures, not the use of natural gas. Natural gas buses have onboard gas detectors and other safety devices such as tank safety valves that allow fuel flow only when the engine is on. Also, the tanks must be inspected by the U.S. Department of Transportation after certain periods of use.

There are some different safety concerns with CNG buses than diesel fuel buses, such as greater breaking distance due to increased fuel storage system weight. This is a relatively small concern, however, because the fuel system is a small fraction of a bus’ total weight. CNG buses also might accelerate more slowly than their diesel counterparts.

Focus on Operations

It takes a great deal of effort and expertise to locate and extract natural gas. Located miles beneath the surface, high-tech engineering practices are coordinated with environmental guidelines to bring up the gas and process it in the safest manner possible. This can take months to complete. The processes employed for natural gas exploration and production can be found on this page. Please look over these fact sheets for detailed information on horizontal drilling, hydraulic fracturing and water usage.


The history of CNG as a transportation fuel dates back to World War II.  Natural gas vehicles are a proven technology that have been enhanced and refined over the years into a convenient and extremely safe method of transportation. Daily use of natural gas vehicles can be found throughout the United States in a variety of applications.

Demand CNG NOW!

Compressed Natural GasIt’s up to us, America’s consumers, to insist that legislators implement policies to accelerate growth in NGV manufacturing, purchase and use. This includes incentives for cash-strapped automakers to produce a wider range of natural gas vehicles, incentives for American consumers, governments, and businesses to buy natural gas vehicles and incentives for the installation of CNG dispensers at more gasoline retailers. We need to demand to be heard and give Americans the opportunity to use a clean, American fuel.