Washington

Accusations of mismanagement and theft at the United States' most venerable nuclear-weapons laboratory have prompted the resignations of its top two managers.

On 2 January, John Browne and Joseph Salgado stepped down as director and deputy director of the Los Alamos National Laboratory in New Mexico. Their resignations are believed to have been requested by the University of California (UC), which has overseen the laboratory for the US government since 1943.

Congressional and Department of Energy officials are now demanding a review of the university's contract to manage the lab, whose once-formidable reputation has been tarnished by a succession of recent crises.

The resignations stemmed from allegations made in November, when two independent investigators hired by the lab released documents that they said showed endemic theft and credit-card fraud at Los Alamos. Laboratory officials said the alleged problems amounted to only a few million dollars, against the lab's annual budget of $1.3 billion for goods and services. Shortly afterwards, the lab fired the investigators, without giving any public explanation.

This angered the congressional and federal officials who oversee the lab. “The treatment of whistleblowers is a big issue for us,” said a staff member on a congressional committee investigating the situation at the lab. This sentiment was strongly echoed by energy secretary Spencer Abraham in a letter sent to Richard Atkinson, the UC president, on 24 December, in which he said that the two investigators' dismissals were “of most immediate concern”. Abraham had already dispatched the energy department's inspector general to look into the matter.

The incident is the latest in a string of embarrassing mishaps for the lab, which was the birthplace of the atomic bomb. In 1999, Los Alamos scientist Wen Ho Lee was accused of passing nuclear secrets to a foreign power (see Nature 398, 96; 199910.1038/18079); he was later acquitted. In 2000, computer drives containing secret bomb data disappeared from a secure vault and later reappeared behind a photocopier (see Nature 405, 725; 200010.1038/35015770). Earlier that year, a nearby forest fire had threatened sensitive areas of the lab.

“A whole string of things have been happening over the past few years,” says Robert Civiak, a consultant who until 1999 worked as White House budget examiner for the energy department's national security programmes. “This could just be the straw that breaks the camel's back.”

The series of incidents caused the energy department to put stipulations in its January 2001 contract with UC aimed at bolstering supervision and security at the lab. Chief among these was the appointment of a head of laboratory management for all the labs administered by the university. Retired Ford Motor Company vice-president John McTague was appointed, but resigned in November after trying to appoint a Los Alamos scientist to head the other main scientific laboratory in the US nuclear-weapons programme, the Lawrence Livermore National Laboratory in California. That appointment was overturned by the White House after strenuous objections from Livermore researchers (see Nature 417, 3; 2002doi:10.1038/417003b).

In his 24 December letter, Abraham said that the energy department would conduct a review of UC's contract to manage the lab, which would be completed by May. “There's more reason now than ever for the energy department to consider a body other than the University of California,” says Ray Kidder, a retired nuclear-weapons scientist from Lawrence Livermore. But Kidder thinks that a change in the contract would damage the morale of scientists at Los Alamos.

Possible contenders for the contract include the University of Texas, which expressed interest in it in 2001, and the Battelle Corporation of Columbus, Ohio, which runs other energy department labs, including the Oak Ridge National Laboratory in Tennessee and (jointly with Stony Brook University) the Brookhaven National Laboratory in New York.

Vice-Admiral George Nanos, who previously ran the Threat Reduction Directorate at Los Alamos, will serve as the lab's interim director.