Services covered under Section 218 Agreements executed and effective on or before July 1, 1991, are not affected by the mandatory coverage provisions, regardless of whether such services are performed by employees who are or are not members of their employer's retirement system. Such services continue to be covered under the State’s Agreement after July 1, 1991.

A State may continue to expand voluntary coverage under its Section 218 Agreement for services performed by State or local employees. The Social Security Administration (SSA) will execute such Agreements even though mandatory coverage may apply to some or all of the services involved. Once the State expands voluntary coverage, employees performing the voluntarily covered position will be covered for Social Security regardless of whether they are a member of a qualified retirement system.

Medicare HI-only coverage obtained under a Section 218 Agreement on or before July 1, 1991, continues after July 1, 1991.

If a Section 218 Agreement for Medicare HI-only coverage was retroactive to periods on or before July 1, 1991, services performed by employees on or before July 1, 1991 are covered for Medicare under the Agreement. However, services performed after July 1, 1991 by employees who are not members of a qualified retirement system are covered mandatorily for Social Security.

An Error Modification should list the date the coverage error began as the effective date regardless of whether the coverage error began prior to, on, or after July 1, 1991 (see SL 40001.465B). Coverage will continue from the effective date forward.

Under a Section 218 Agreement, a State has the option to exclude certain services from coverage. If the Agreement does not specifically exclude these services, they are covered. Beginning after July 1, 1991, mandatory coverage may apply to services that were excluded optionally by the State, unless the service is excluded from mandatory coverage by law (SL 50001.501D). As with all mandatory coverage, an employee in one of these excluded positions will be covered mandatorily unless the employee participates in a qualified retirement system.