Minn. Stat. § 352.90

It is the policy of the legislature to provide special retirement benefits for and special contributions by certain correctional employees who may be required to retire at an early age because they lose the mental or physical capacity required to maintain the safety, security, discipline, and custody of inmates at state correctional facilities or of patients at the Minnesota Security Hospital, of patients in the Minnesota sex offender program, or of patients in the Minnesota Specialty Health System-Cambridge.