Section 3O. Each city and town shall provide by ordinance or by-law for the appointment of an inspector of gas piping and gas appliances in buildings who shall be a licensed plumber or licensed gas fitter. Said inspector shall enforce the rules and regulations adopted by the board established under section twelve H of chapter twenty-five.

Said inspector shall also issue permits for the installation of containers of liquefied petroleum gas, and he shall inspect such installation and the regulating equipment used in connection therewith. He shall notify the head of the fire department, as defined in section one of chapter one hundred and forty-eight, of each permit so issued and the location of each container of liquefied petroleum gas installed thereunder.

A town in which the only gas available is undiluted liquefied petroleum gas and in which no licensed plumber or licensed gas fitter is available for appointment as an inspector of gas piping and gas appliances in buildings may appoint a licensed undiluted liquefied petroleum gas installer to inspect gas piping and gas appliances in buildings. The appointing authority of such town shall certify to the board established under section twelve H of chapter twenty-five that the only gas available in such town is undiluted liquefied petroleum gas and that a licensed plumber or licensed gas fitter is not available therein.

If a city or town fails to provide for the appointment of a gas inspector as required by this section, said board shall cause gas inspections to be made therein, so long as such failure continues, by a gas inspector of a city or town within the same county who shall be designated by the board from time to time. The cost of such inspections shall be paid by the city or town which failed to provide for the appointment of a gas inspector.