[Description of Hazard] Are stored in cylinders under significant pressure. Regardless of the gas inside the cylinder, any gas under pressure posses an inherent physical hazard. [Examples] Hydrogen, Nitrogen, Acetylene and Oxygen [Classification] 
Compressed Gases
I r r i t a n t s
S e n s i t i z e r s
C o r r o s i v e s
C a r c i n o g e n s
S y s t e m i c P o i s o n s
F l a m m a b l e s
C o m b u s t i b l e L i q u i d s
C o m p r e s s e d G a s e s
R e a c t i v e s