CA Health & Safety Code § 7054.7 (2021)
2021 California Code|Health and Safety Code - HSC|DIVISION 7 - DEAD BODIES|PART 1 - GENERAL PROVISIONS|CHAPTER 2 - General Provisions|Section 7054.7.

7054.7.  (a)  Except with the express written permission of the person entitled to control the disposition of the remains, no person shall: (1)  Cremate the remains of more than one person at the same time in the same cremation chamber, or introduce the remains of a second person into a cremation chamber until incineration of any preceding remains has been terminated and reasonable efforts have been employed to remove all fragments of the preceding remains. The fact that there is residue in the cremation chamber or other equipment or any container used in a prior cremation is not a violation of this section. (2)  Dispose of or scatter cremated remains in a manner or in a location that the remains are commingled with those of another person. This paragraph shall not apply to the scattering of cremated remains at sea from individual containers or to the disposal in a dedicated cemetery of accumulated residue removed from a cremation chamber or other cremation equipment. (3)  Place cremated or uncremated remains of more than one person in the same container or the same interment space. This paragraph shall not apply to the following: (A)  Interment of members of the same family in a common container designed for the cremated remains of more than one person. (B)  Interment in a space or container that has been previously designated at the time of sale as being intended for the interment of remains of more than one person. (C)  Disposal in a dedicated cemetery of residue removed from a cremation chamber or other cremation equipment. (b)  Written acknowledgement from the person entitled to control the disposition of the cremated remains shall be obtained by the person with whom arrangements are made for disposition of the remains on a form that includes, but is not limited to, the following information: “The human body burns with the casket, container, or other material in the cremation chamber. Some bone fragments are not combustible at the incineration temperature and, as a result, remain in the cremation chamber. During the cremation, the contents of the chamber may be moved to facilitate incineration. The chamber is composed of ceramic or other material which disintegrates slightly during each cremation and the product of that disintegration is commingled with the cremated remains. Nearly all of the contents of the cremation chamber, consisting of the cremated remains, disintegrated chamber material, and small amounts of residue from previous cremations, are removed together and crushed, pulverized, or ground to facilitate inurnment or scattering. Some residue remains in the cracks and uneven places of the chamber. Periodically, the accumulation of this residue is removed and interred in a dedicated cemetery property, or scattered at sea.” The acknowledgment shall be filed and retained, for at least five years, by the person who disposes of or inters the remains. (c)  Any person, including any corporation or partnership, knowingly violating any provision of this section is guilty of a misdemeanor. (Amended by Stats. 1994, Ch. 570, Sec. 7. Effective January 1, 1995.)