See 3.90 Park District Employees for a discussion of coverage of these instructors. Audits by the IRS and Social Security Social Security coverage for IMRF members is required, except for a limited number of firefighters and police officers, by an agreement between the State of Illinois and the Commissioner of Social Security under Section 218 of the Social Security Act. IMRF members pay Social Security taxes on wages up to the wage base, and IMRF employers pay an equal amount. IMRF employers remit these taxes to the Internal Revenue Service. Applications for benefits and questions about Social Security should be directed to the local Social Security district office or representative or call 1-800-772-1213. have uncovered a substantial number of instructors improperly classified as independent contractors.