Mich. Comp. Laws § 722.113c

Sec. 3c. An individual shall not smoke on the premises of a group child care home or family child care home during the hours of operation of the group child care home or family child care home. The operator of a group child care home or family child care home may permit smoking on the premises during a period other than the hours of operation of that group child care home or family child care home if the operator has provided to a parent or legal guardian of each child participating in a group child care home or family child care home activity notice that smoking on the premises occurs or may occur when the group child care home or family child care home is not in operation. The operator of a group child care home or family child care home shall conspicuously post on the premises a notice that specifies that smoking on the premises is prohibited during the hours of operation of the group child care home or family child care home.