S.C. Code § 39-41-270
The provisions of Section 39-41-260 of the 1976 Code, as amended by Section 1 of Act No. 582 of 1990, apply to all service stations constructed on or after the effective date of this act (June 12, 1990). Also, all existing service stations on the effective date of this act must comply with the revised provisions of Section 39-41-260 within two years of the effective date of this act, except that existing service stations with aboveground storage tanks are not required to comply with the provisions of Section 39-41-260(D) and existing service stations with an aboveground storage tank in excess of twelve thousand gallons liquid capacity on the effective date of this act are exempt from the provisions of Section 39-41-260(B). An imminent hazard to life shall be addressed immediately as referenced in Section 23-9-150 of the 1976 Code. For the purposes of this section and of Section 39-41-260, the term "service station" does not include any utility storage tank facilities which service utility operations, including vehicles, locomotives, or equipment.
S.C. Code § 39-41-270