Mo. Rev. Stat. § 630.945

Beginning July 1, 2013, no state employee, regardless of job classification, who is working in a maximum or intermediate security mental health facility or any portion of a mental health facility which has maximum or intermediate security shall be mandated to work more than twelve hours in any twenty-four hour period unless the department of mental health declares an emergency workforce shortage. The provisions of this section shall not apply on the first Sunday of November each year when the standard time changes according to 15 U.S.C. Section 260a.