N.C. Gen. Stat. § 113A-168
Any outdoor advertising erected or established after May 26, 1975, in violation of the provisions of this Article shall be unlawful and shall constitute a nuisance. The Department of Environmental Quality shall give 30 days' notice by certified mail to the owner of the nonconforming outdoor advertising structure, if such owner is known or can by reasonable diligence be ascertained, to move the outdoor advertising structure or to make it conform to the provisions of this Article and rules and regulations promulgated by the Department of Environmental Quality hereunder. The Department or its agents shall have the right to remove or contract to have removed the nonconforming outdoor advertising at the expense of the said owner if the said owner fails to act within 30 days after receipt of such notice. The Department or its agents or contractor and his employees may enter upon private property for the purpose of removing outdoor advertising prohibited by this Article or its implementing rules without civil or criminal liability.
N.C. Gen. Stat. § 113A-168