California Code, Health and Safety Code - HSC § 7054.9

(1) Reduce the remains of more than one person at the same time and in the same reduction chamber, or introduce the remains of a second person into the reduction chamber until the reduction of preceding remains has been terminated and reasonable efforts have been employed to remove all fragments of preceding remains. The fact that there is residue in the reduction chamber or other equipment or a container used in a prior reduction does not violate this section.

(2) Dispose of reduced human remains in a manner or location that the remains are commingled with those of another person. This paragraph does not apply to the disposition of accumulated residue removed from equipment used in the reduction of human remains.

(3) Place reduced human remains or the remains of more than one person in the same reduced human remains container, except as follows:

(b)(1) A person, including a corporation or partnership, that violates this section is guilty of a misdemeanor.

(2) Written authorization by the person entitled to control the disposition of the remains for the reduction facility to integrate the reduced human remains into the soil of a conservation area, as provided in Section 7054.5, is sufficient to comply with the permission requirement of subdivision (a).