Rapid phase transition or RPT is an explosive boiling phenomenon realized in liquefied natural gas (LNG) incidents, in which LNG vaporizes violently upon coming in contact with water causing what is known as a physical explosion.
During such explosions there is no combustion but rather a huge amount of energy is transferred in the form of heat from the room-temperature water to the LNG at a temperature difference of about 200 K (176.667°C / 350 °F).
It is odorless, tasteless, colorless, and not poisonous but causes asphyxia.
It can cause frostbite due to its cryogenic temperature.
This results in an explosion because the volume occupied by natural gas in its gaseous form is 600 times greater than when its liquefied; this is the phenomenon of rapid phase transition.