Liquid nitrogen is obtained by fractional distillation of liquid air.
Explosions have occurred when liquid air contacts organic matter.
British Dictionary definitions for liquid air
air that has been liquefied by cooling. It is a pale blue and consists mainly of liquid oxygen (boiling pt: –182.9°C) and liquid nitrogen (boiling pt: –195.7°C): used in the production of pure oxygen, nitrogen, and the inert gases, and as a refrigerant