Mass. Gen. Laws ch. 146, § 24: Numbering, stamping or tagging boiler; defacement or removal of number

Section 24. Every boiler which has been inspected by the division shall be numbered either by stamping the number upon the boiler or by attaching a numbered metal tag by a seal or otherwise to the boiler or its fittings. No person except an inspector of the division shall deface or remove any such number or tag.