(CNN) -- Two alcohol-related incidents between 2007 and 2009 involved agents who carry nuclear weapons and materials as they were on transport missions, the Department of Energy's watchdog agency said in a recently released report.
The department's inspector general confirmed a total of 16 alcohol-related incidents involving agents, agent candidates or other personnel of the Office of Secure Transportation, according to a report dated November 17. Of the 16 cases cited, two "were of greatest concern," the report said, "because they occurred during secure transportation missions" while the agents were checked into hotels.
In the most recent incident, in 2009, two agents were handcuffed and briefly detained after an incident at a bar. Another incident occurred in 2007, when an agent was arrested for public intoxication.
None of the incidents involved intoxicated driving, said Felicia Jones, spokeswoman for the inspector general's office.
Jones said that because of security concerns regarding the practice of using overnight "safe harbors" on extended transport missions, the locations of the incidents could not be disclosed.
The Office of Secure Transportation employs a force of about 600 agents, agent candidates and other personnel to transport nuclear weapons, components and materials.
"While OST appeared to have been proactive in addressing the use of alcohol," the report stated, "concerns expressed by some OST managers and the number of alcohol-related incidents ...suggests that further action may be needed."
According to the Energy Department, the Office of Secure Transportation's policy on alcohol use by agents includes:
-- Testing for alcohol at least once a year or when there is reasonable suspicion of alcohol use;
-- Sending agents home if they have blood-alcohol concentrations of 0.02 percent or higher;
-- Prohibiting drinking within 10 hours of scheduled work.
Damien LaVera, public affairs director for the National Nuclear Security Administration, which oversees the Office of Secure Transportation, noted that nuclear materials have been transported "more than 100 million miles without a single fatal accident or any release of radiation."
"The inspector general review did not find any evidence of a systemic problem, nor was there any evidence that any of our agents were driving while intoxicated while on duty," LaVera noted in an e-mail to CNN.
"Appropriate disciplinary action was taken in both of these cases," LaVera said, "and NNSA has established even tougher rules on alcohol use and a new alcohol testing requirement."
Jones, the inspector general's office spokeswoman, said the nature of the disciplinary actions could not be disclosed.
CNN's Matt Cherry and Cameron Tankersley contributed to this report.