Mass. Gen. Laws ch. 98 § 28A
Meters for measuring liquefied petroleum gas sold in the vapor state and household type liquid petroleum meters shall be sealed by the manufacturer thereof as hereinafter provided or by a sealer of weights and measures in the town where the meter is used. The deputy director of standards shall prescribe regulations including specifications and tolerances governing the testing and sealing of such meters by the manufacturers and method of determining quantity of liquefied petroleum gas, and other liquid petroleum heating oils, and may authorize any manufacturer to seal such meters upon written agreement to conform to such regulations. The deputy director may at any time for cause revoke the authority so given by him to any manufacturer. The deputy director or his inspectors under his direction shall test and seal or condemn, according to the results of such test, all meters for measuring liquefied petroleum gas sold in the liquid state. For the purposes of this section the term "liquefied petroleum gas" shall mean and include any material which is composed predominantly of any of the following hydrocarbons or mixtures of the same: propane, propylene, butane (normal or isobutane) and butylene; and the term "household type liquid petroleum meters" shall mean positive displacement meters installed between the liquid heating oil storage tank and the oil burner for the purpose of determining the quantity of liquid heating oil consumed.
Mass. Gen. Laws ch. 98, § 28A