Michigan Compiled Laws, Chapter 324. Natural Resources and Environmental Protection § 324.8507

Sec. 8507. (1) Each licensee and registrant shall maintain for a period of 3 years a record of quantities and grades of fertilizer and soil conditioner sold or distributed by the licensee or registrant and shall make the records available for inspection and audit during normal business hours on request of the department. Each distributor shall maintain for a period of 3 years shipping data such as invoices and freight bills pertaining to fertilizer and soil conditioner that establish date and origin of the shipment, and shall make the records available for inspection and audit on request of the department.

(2) Tonnage payments, tonnage reports, or other information furnished or obtained under this part shall not be disclosed in a way that will divulge the business operations of any 1 person.