On December 20, 2018, the NRC issued a Notice of Violation and Proposed Imposition Civil Penalty in the amount of $29,000 to Terracon Consultants, Inc. (licensee) for a Severity Level III problem associated with two related portable nuclear gauge violations. The violations involved the licensee's failure to (1) use a minimum of two independent physical barriers to secure a portable nuclear gauge from unauthorized removal when not under the control and constant surveillance of the licensee in accordance with Title 10 of the Code of Federal Regulations (10 CFR) 30.34(i); and (2) maintain constant surveillance of a portable nuclear gauge that was not in storage in accordance with 10 CFR 20.1802. Specifically, on June 28, 2018, a licensee portable nuclear gauge user placed the gauge on the tailgate of pickup truck for approximately 30 minutes while the gauge user was inside the cab of the truck. The gauge user subsequently drove the vehicle off of the work site and onto a public highway with the gauge still in the unsecured position on the tailgate of the pickup truck.