(1) As used in KRS 234.100 to 234.160 and 234.990 the term "liquefied petroleum gas" means and includes any material which is composed predominantly of any of the following hydrocarbons, or mixtures of them, whether in the liquid or in the gaseous states: propane, propylene, butane (normal butane or isobutane), and butylene.
(2) "Commissioner" means commissioner of housing, buildings and construction.