The type of material found in dot class 2 division 2 is?

"Non-flammable compressed gas" is the formal terminology. This class/division includes carbon dioxide (co2) cylinders, air tanks, and many industrial gasses described as "inert". Flammable gasses/aerosols, and toxic gasses/aerosols are also in class 2, but different divisions (2.1, and 2.3 respectively)