Mich. Comp. Laws § 409.110

Sec. 10. (1) A minor under 16 years of age whose employment is subject to this act may be employed only as follows: (a) During a time that is outside school hours. (b) For not more than 3 hours per day during a week when school is in session. (c) Between the hours of 7 a.m. and 9 p.m. during the period that begins on June 1 and ends on Labor Day. (d) Between the hours of 7 a.m. and 7 p.m. during the period that begins on the date immediately following Labor Day and ends on May 31. (e) For not more than 18 hours during a week when school is in session. (f) For not more than 40 hours during a week that is not a week when school is in session. (2) As used in this section: (a) "Outside school hours" means that term as defined in 29 CFR 570.35. (b) "School hours" means that term as defined in 29 CFR 570.35. (c) "Week" means that term as defined in 29 CFR 570.35. (d) "Week when school is in session" means that term as defined in 29 CFR 570.35.