Natural gas use does not pose any risk to soil or groundwater because it is lighter than air and will rise into the atmosphere if released. In the event of a motor vehicle accident involving a fire, natural gas fuel storage systems on vehicles are designed to release fuel from the storage tanks, so as to minimize risk to vehicle occupants and the public.
There is no risk of site contamination related to natural gas fuel storage tanks. Both compressed natural gas (CNG) and liquefied natural gas (LNG) stations incorporate above ground fuel storage tanks. Sophisticated monitoring systems are used on a 24/7 basis to monitor station conditions. If a fuel storage tank were to leak, the fuel would vent to atmosphere. An LNG leak could create a pool, but codes and regulations require that containment structures be built around LNG tanks to contain any fuel in the event of a leak. When exposed to atmospheric conditions, LNG will change from a liquid to a gas, so there is no risk of liquid fuel contaminating soil or groundwater.