Mich. Comp. Laws § 286.372a

Sec. 2a. (1) Each sealed storage room, sealed storage space, or sealed storage building used as a controlled atmosphere storage facility for fruits or vegetables shall be constructed of materials that will allow for the establishment and maintenance of the required levels of carbon dioxide, oxygen, and temperature and that are acceptable to the director. (2) Each sealed storage room, sealed storage space, or sealed storage building shall have a Fahrenheit thermometer properly installed and maintained. An approved gas analyzer for the measurement of carbon dioxide and oxygen gases shall be readily accessible to all sealed rooms or units.