Nitrogen gas is not flammable. It will not readily burn or support combustion. It is an inert material, and this inert quality makes it useful in industrial applications to prevent combustion of other materials.
Nitrogen comprises approximately 78 percent of the Earth's atmosphere. There are approximately 4 quadrillion tons of the inert gas on the planet. Despite this, pure nitrogen can asphyxiate, as humans require oxygen to breathe to survive. Nitrogen will dissolve into human blood during time spent in depths of greater quantity, requiring divers and spelunkers to slowly return to a sea level altitude to avoid decompression sickness.