S.C. Code Ann. § 59-25-57

Notwithstanding another provision of law, school districts uniformly may negotiate salaries below the school district salary schedule for the 2014-2015 school year for retired teachers who are not participants in the Teacher and Employee Retention Incentive program. Thereafter, school districts annually may continue to uniformly negotiate salaries below the school district salary schedule for retired teachers who are not participants in the Teacher and Employee Retention Incentive program for each upcoming school year through the 2019-2020 school year. The provisions of this section expire on July 1, 2020.