S.C. Code Ann. § 41-7-30 – Certain acts required of employee as condition of employment or continuance of employment made unlawful

It shall be unlawful for any employer:

(1) To require any employee, as a condition of employment, or of continuance of employment, to be or become or remain a member or affiliate of any labor organization or agency;
(2) To require any employee, as a condition of employment, or of continuance of employment, to abstain or refrain from membership in any labor organization; or
(3) To require any employee, as a condition of employment, or of continuance of employment, to pay any fees, dues, assessments or other charges or sums of money whatsoever to any person or organization.