Every person, copartnership, corporation or other association now or hereafter engaged in the business of producing from natural deposits and/or carrying or transporting natural gas and/or crude oil or petroleum or the products thereof for hire, by pipelines within this state shall be a common carrier within the meaning and subject to the provisions of this title: PROVIDED, HOWEVER, That the provisions of this section shall not apply to distribution systems owned and operated under franchise for the sale, delivery, or distribution of natural gas at retail.