Cal. Health & Safety Code § 8342

No crematory shall make or enforce any rules requiring that human remains be placed in a casket before cremation or that human remains be cremated in a casket, nor shall a crematory refuse to accept human remains for cremation for the reason that they are not in a casket. Every director, officer, agent or representative of a crematory who violates this section is guilty of a misdemeanor. Nothing in this section shall be construed to prohibit the requiring of some type of container or disposal unit.