The CEO shall cause the compliance order, or a copy thereof, to be served on the owner of the affected property personally or by registered or certified mail. The Officer shall be permitted, but not required, to cause the compliance order, or a copy thereof, to be served on any builder, architect, tenant, contractor, subcontractor, construction superintendent, or their agents, or any other person taking part or assisting in work being performed at the affected property personally or by registered or certified mail; provided, however, that failure to serve any person mentioned in this sentence shall not affect the efficacy of the compliance order.