Mo. Rev. Stat. § 292.040: Minor not to clean or work in certain places about machinery.

No minor shall be required to clean any part of the mill, gearing or machinery while it is in motion in such establishment, nor shall any minor under the age of sixteen years be required to work between the fixed and traversing or the traversing parts of any machine while it is in motion by the action of steam, water, electricity or other mechanical power.