CNG cylinders are much stronger and safer than gasoline tanks. The design of the cylinder is subject to a number of severe abuse tests such as heat and pressure extremes, dropping, dragging, crushing and even gunfire (Only a round from an AR15 was able to penetrate the cylinder at which point it safely discharged all pressurized contents without incident). The fuel system is fitted with valves, backup valves, emergency shut-off valves and pressure relief devices making this system much safer than its gasoline counterpart. All CNG cylinders must be DOT approved and are inspected every 3 years within their 20 year lifespan. Worldwide, millions of vehicle platforms have been safely driving on CNG for many years including federal, state, and local government fleets.