49 C.F.R. § 172.415
NON-FLAMMABLE GAS label
(a) Except for size and color, the NON-FLAMMABLE GAS label must be as follows:

(b) In addition to complying with § 172.407, the background color on the NON-FLAMMABLE GAS label must be green.
(a) Except for size and color, the NON-FLAMMABLE GAS label must be as follows:

(b) In addition to complying with § 172.407, the background color on the NON-FLAMMABLE GAS label must be green.