The term "liquefied petroleum gas", as used in this chapter, means and includes any material which is composed predominantly of any of the following hydrocarbons, or mixtures of the same: propane, propylene, butane (normal butane or isobutane), and butylenes.
Liquefied petroleum gas defined
N.D.C.C. § 18-09-01 — under Liquefied Petroleum Gas Regulation.
N.D.C.C. § 18-09-01