Mo. Rev. Stat. § 590.210

Notwithstanding any other provision of law, any law enforcement agency in this state may supplement such agency's workforce as necessary with qualified retired peace officers as defined in subsection 12 of section 571.030 when a disaster or emergency has been proclaimed by the governor or when there is a national emergency. Retirees assisting law enforcement agencies under the provisions of this section shall be in compliance with the annual firearms training and qualification standards for retired law enforcement officers carrying concealed firearms established by the department of public safety under section 650.030. Any compensation awarded to retirees for service under this section shall be paid by the law enforcement agency.