S.C. Code Ann. § 46-25-50: Sales between and to importers, registrants, and manipulators.

Nothing in this chapter shall be construed to restrict or avoid sales or exchange of commercial fertilizers to each other by importers, registrants, or manipulators who mix fertilizer materials for sale or as preventing the free and unrestricted shipments of commercial fertilizers to registrants or manipulators who have registered their brands as required by the provisions of this chapter.