R.I. Gen. Laws § 36-10.3-3: Supplemental participation for local public employers.

Employers that include job positions, other than public safety positions, that do not participate in Social Security under the Federal Old Age, Survivors and Disability Income program, but which currently contribute to ERS or MERS on behalf of such positions, shall make supplemental contributions to the plan on behalf of regular members in such positions as a supplemental employer in accordance with § 36-10.3-6(a). A supplemental employer may request a different level of supplemental contributions in accordance with § 36-10.3-6(b) by an ordinance or resolution of its governing body. A regular member in such positions shall be referred to as a “supplemental member” in § 36-10.3-6.