WASHINGTON—Government agents hired to drive nuclear weapons and components in trucks sometimes got drunk on the job, including an incident last year when two agents were detained by police at a local bar during a convoy mission, according to a report Monday by the U.S. Energy Department's watchdog.

The department's assistant inspector general, Sandra D. Bruce, said her office reviewed 16 alcohol-related incidents involving agents, candidate-agents and others from the government's Office of Secure Transportation between 2007 through 2009. There are nearly 600 federal agents who ship nuclear weapons, weapon components and special nuclear material across the U.S.

The report said two incidents in particular raised red flags because they happened during "secure transportation missions,'' with agents checked into local hotels and vehicles in "safe harbor," or secure conditions.

One of those occurred in 2007, when an agent was arrested for public intoxication; the other happened last year, when police handcuffed and temporarily detained two agents after an incident at a local bar.