This regulation shall be effective in all areas of the Saco River corridor as defined in Title 38 M.R.S.A. Section 953 and shall apply to all nonconforming uses or structures in existence prior to March 19, 1974, and to all nonconforming uses or structures established after March 19, 1974, and which legally exist as a result of the granting of a variance by the commission.
94-412 C.M.R. ch. 107, § 1