Michigan Compiled Laws, Chapter 324. Natural Resources and Environmental Protection § 324.5536

Sec. 5536. In determining under what conditions and to what extent a variance from a rule or regulation that would not violate the clean air act may be granted, the department shall give due recognition to the progress which the person requesting the variance has made in eliminating or preventing air pollution. The department shall consider the reasonableness of granting a variance conditioned upon the person effecting a partial control of the particular air pollution or a progressive control of the air pollution over a period of time that it considers reasonable under all the circumstances or the department may prescribe other and different reasonable requirements with which the person receiving the variance shall comply.