Section 43M. Except as otherwise provided by law, or in case of a dead body being rightfully carried through or removed from the commonwealth for the purpose of burial or disposition elsewhere, every dead body of a human being dying within the commonwealth, and the remains of any body after dissection therein, shall be decently buried, entombed in a mausoleum, vault or tomb or cremated within a reasonable time after death. The permanent disposition of such bodies or remains shall be by interment in the earth or deposit in a chamber, vault or tomb of a cemetery owned, maintained and operated in accordance with the laws of this commonwealth, by deposit in a crypt of a mausoleum, or by cremation. The remains of a human body after cremation may be deposited in a niche of a columbarium or a crypt of a mausoleum, buried or disposed of in any manner not contrary to law. Notwithstanding any general or special law to the contrary, a funeral establishment in possession of the cremated remains of a human body which is not claimed by a next-of-kin or duly authorized representative within 12 months after the date of cremation may have the remains interred or placed in a common grave, niche, or crypt in a cemetery, or scattered in an area of the cemetery designated for that purpose; provided, however, that if the deceased is a veteran of the United States Armed Forces the deceased shall be interred at a veterans' cemetery. Each cemetery and funeral establishment shall maintain permanent records of such disposition. There shall be no liability for a funeral establishment, cemetery or crematory, or any employee or agent thereof that disposes of unclaimed cremated remains in accordance with this section. Each municipality or cemetery corporation shall maintain records which identify the name, if known, of the dead human body or remains in each burial lot, tomb or vault under its control. No deposit of the bodies or remains of the human dead shall be made in a single chamber, vault or tomb wholly or partly above the natural surface of the ground unless the part thereof below such surface is of a permanent character, constructed of materials capable of withstanding extreme climatic conditions, waterproof and air tight, and capable of being sealed permanently to prevent all escape of effluvia, and unless the part thereof above the natural surface of the ground is constructed of natural stone of a standard not less than that required by the United States government for monuments erected in national cemeteries, of durability sufficient to withstand all conditions of weather.