WASHINGTON _ The unmarked 18-wheelers ply the nation's interstates and two-lane highways, logging 3 million miles a year hauling the most lethal cargo there is: nuclear bombs.
The covert fleet, which shuttles warheads from missile silos, bomber bases and submarine docks to nuclear weapons labs across the country, is operated by the Office of Secure Transportation, a troubled agency within the U.S. Department of Energy so cloaked in secrecy that few people outside the government know it exists.
The $237 million-a-year agency operates a fleet of 42 tractor-trailers, staffed by highly armed couriers, many of them veterans of the Iraq and Afghanistan wars, responsible for making sure nuclear weapons and components pass through foggy mountain passes and urban traffic jams without incident.
The transportation office is about to become more crucial than ever as the U.S. embarks on a $1 trillion upgrade of the nuclear arsenal that will require thousands of additional warhead shipments over the next 15 years.
The increased workload will hit an agency already struggling with problems of forced overtime, high driver turnover, old trucks and poor worker morale _ raising questions about its ability to keep nuclear shipments safe from attack in an era of more sophisticated terrorism.
"We are going to be having an increase in the movements of weapons in coming years and we should be worried," said Robert Alvarez, a former deputy assistant Energy secretary who now focuses on nuclear and energy issues for the Institute for Policy Studies in Washington. "We always have to assume the worst-case scenario when we are hauling nuclear weapons around the country."
That worst case would be a terrorist group hijacking a truck and obtaining a multi-kiloton hydrogen bomb.
"The terror threat is significant," said one high-level Energy Department official, who spoke on condition of anonymity because he was not authorized to discuss the program publicly. "If you are in one of the communities along the route, you have something to worry about."
The Los Angeles Times/Tribune Washington Bureau reviewed government documents dating back two decades and interviewed dozens of government officials, former military officers and arms control advocates to examine the agency. The picture that emerges is an organization hampered by an insular management, a crisis of morale among the rank-and-file and outdated equipment.
Among the findings of the Times investigation:
_The agency is 48 agents short of its planned staffing of 370, a result of budget cuts. Weapons and tactics classes were canceled in 2011 and 2012 for lack of money.
_More than a third of the workforce has been putting in more than 900 hours a year of overtime, which former couriers and Energy Department officials say has contributed to a breakdown in morale and rapid turnover.
_In 2010, an inquiry by the Energy Department's inspector general inquiry found widespread alcohol problems. It cited 16 alcohol-related incidents over a three-year period, including an agent on a 2007 mission who was arrested for public intoxication and two agents on a 2009 mission who were handcuffed and detained by police after a fight at a bar.
_In 2014, the commander of the agency's operation at the Y12 National Security Complex in Tennessee threatened to kill an employee in an altercation, but no disciplinary action was taken.
_The agency's top executive in 2009 was charged with drunk driving after police found him parked on a sidewalk with an open bottle of beer and a blood-alcohol concentration of 0.15 percent, nearly twice the legal limit, according to New Mexico court records.
_The agency's truck fleet is antiquated by commercial standards and well past its operational life even under the department's own guidelines. About half the tractors are more than 15 years old. The high-security trailers used by the agency are even older, designed before the current era of terrorist threats.
How the agency wound up in this state is a story of neglect that begins at the end of the Cold War.
After the Soviet Union broke apart in 1991 and chances of a nuclear attack faded, the U.S. dramatically reduced its nuclear stockpile and gave it less attention as military priorities shifted.
The transportation office budget stagnated, and was hit by big cuts in some years, leading to staffing shortages and delays in updating equipment. Drivers had to start working long hours of overtime, which led to morale problems and management breakdowns.
Despite these problems, the agency asserts that it has maintained a high level of security and has never lost a weapon, though it has been involved in several accidents.
The agency denied repeated requests for interviews with top managers. It issued a statement touting its safety record: "For more than 40 years _ even after driving the equivalent distance of a trip to Mars and back _ no cargo has ever been damaged in transit," it said.
Yet even one of its most stringent security measures was breached, the inspector general found in 2014, when an "unauthorized" employee had access to a nuclear weapon on a convoy mission.
According to two knowledgeable sources, the person in question had lost his human reliability rating, which is based on screening for drugs, alcohol abuse or mental health problems, among other things. Under the agency's rules, the unidentified employee should not have been allowed on the mission. The employee was discovered at a military base and removed from the assignment.
Overseers in Congress say the transportation office is less prepared for an attack than it used to be.
"It clearly needs a reinvestment," Rep. Mac Thornberry, the Texas Republican who chairs the House Armed Services Committee, said in an interview. "Like other parts of the nuclear enterprise, the agency has been allowed to atrophy as the country has focused on other things."
