Natural Gas is the most explosive element on the earth. Due to hydrogen and helium compounds the explosion level of the gas will be very high. This is What Happens When Oil Tank Burns. When an oil tank burn the gas in the tank will not completely burn in a second it takes some time to reach the the points. Because there will be less air in the container the gas will not burn completely in sudden.
After some when there will be space to enter air into the container the huge explosion takes place. It would be easy to stop the fire before the air enters into the container but once if the air enters the container it range of fire will be very very huge and cannot be stopped by simple fire engines. These fire may effects up to high range. People need to be very careful at this kind of places or else they might get into risk. You may like to see Video must be Watched-Volcano Eruption .
Source : funnyvideosandcrash