Butane designated as certified butane under § 1090.1000(e) for use under the butane blending provisions of § 1090.1320(b) must meet the following per-gallon standards:
(a) Butane content. Minimum 85 volume percent.
(b) Benzene content. Maximum 0.03 volume percent.
(c) Sulfur content. Maximum 10 ppm.
(d) Chemical composition. Be composed solely of carbon, hydrogen, oxygen, nitrogen, and sulfur.