California Code, Health and Safety Code - HSC § 25110.11

(a) “Contained gaseous material,” for purposes of subdivision (a) of Section 25124 or any other provision of this chapter, means any gas that is contained in an enclosed cylinder or other enclosed container.

(b) Notwithstanding subdivision (a), “contained gaseous material” does not include any exhaust or flue gas, or other vapor stream, or any air or exhaust gas stream that is filtered or otherwise processed to remove particulates, dusts, or other air pollutants, regardless of the source.