Maryland Commercial Law Section 18-302

      Except as provided by § 7-601 of this article, a warehouseman or his officer, agent, or employee may not issue or aid in issuing a duplicate or additional negotiable warehouse receipt for any goods:

            (1)      Without a conspicuous notation on its face of the word "duplicate";

            (2)      With knowledge that the original warehouse receipt for the goods is outstanding and uncancelled.