S.C. Code § 9-1-1580
Should the system report and certify to the Board that the disability beneficiary is engaged in or is able to engage in a gainful occupation paying more than the difference between his retirement allowance and his average final compensation and should the Board concur in the report, then the amount of his disability retirement allowance must be reduced to an amount which, together with the amount earnable by him, equals the amount of his average final compensation. Should his earning capacity be later changed, the amount of his disability retirement allowance may be further modified. The new disability retirement allowance shall not exceed the amount of the disability retirement allowance originally granted nor an amount which, when added to the amount earnable by the beneficiary, equals the amount of his average final compensation.
The average final compensation may be increased up to ten percent annually to adjust for inflation.
If the disability retirement allowance is eliminated as a result of this section for a period of five consecutive years, all rights in and to his disability retirement allowance are revoked. The member then is entitled to a deferred retirement allowance as provided in Section 9-1-1650 based upon his average final compensation and creditable service at his date of disability retirement.
After age sixty-five, a disability retiree is subject to the same earnings limitation as a service retiree.
S.C. Code § 9-1-1580