Employees engaged in any kind of mining, mechanical, chemical manufacturing, or smelting business may not work more than 8 hours a day in a 24-hour period without their consent (MO Rev. Stat. Sec. 290.020).
No rail employee may work unless the employee has had at least 8 consecutive hours off duty during the preceding 24 hours (MO Admin. Code Tit. 4 Sec. 265-9.070). Employees in safety-sensitive jobs must have 10 hours of rest before going back on duty after working for 12 hours.
Time on duty includes interim rest periods up to 1 hour and time spent transporting an employee to an assignment.
In an emergency, an employee may work up to 15 hours but may not work more than the 12-hour limit for more than 2 days in a 7-day period.
Missouri places strict limits on the hours that may be worked by employees under the age of 18, especially those of compulsory school age.