225 ILCS 411/20-40

A cemetery authority shall not knowingly bury human remains from multiple persons, known or unknown, in the same casket or grave space with the exception of (1) human remains that are placed in individual containers, (2) a mass casualty event, either natural or man-made, or (3) an arrangement made pursuant to a lawful contract with a consumer that complies with the requirements of Section 20-10 of this Act.