On June 1, 2016, the NRC issued a Notice of Violation to Thielsch Engineering, Inc., for a Severity Level III problem for two related violations. The violations involved a failure to control and maintain constant surveillance or failure to use two independent physical controls that form tangible barriers to secure a portable gauge from unauthorized removal as required by 10 CFR 20.1802 and 30.34(i), and a failure to have a lock on a portable gauge or have the gauge contained in an outer locked container in accordance with its NRC license condition. Specifically, on January 20, 2016, a portable gauze was left unattended and uncontrolled at the U.S. Naval Base jobsite and it was not secured with any physical controls that form tangible barriers to secure it from unauthorized removal. The unattended gauge was not under the direct surveillance of the authorized user and did not have a lock on the gauge or maintained inside a locked container designed to prevent unauthorized or accidental removal of the sealed source from its shielded position.