On November 21, 2017, the NRC issued a Notice of Violation to Midwest Engineering and Testing, Inc. for a Severity Level III violation. The violation 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 20.1801 and 30.34(i). Specifically, on June 22, 2017, the licensee's technician placed the gauge containing licensed material in a construction trailer and left the site without using the locking mechanism on either of the trailer's two doors, resulting in zero barriers to secure the gauge from unauthorized removal.