In any instance where the Department learns or has reasonable grounds to believe that any person is erecting or adding to a structure that would be subject to the provisions of this Act but concerning which no application for a permit has been filed, it may on its own motion issue an order to such person to appear before the Department and show cause why an application for a permit to erect or add to the structure need not be obtained. A date for a hearing thereon shall be set out in such order.