The tens of millions of dollars spent to upgrade security at Los Alamos National Laboratory make the findings of an investigation into a recent security breach at the nuclear weapons lab even more troubling, says the Energy Department's inspector general.

In a two-page memo, Inspector General Gregory H. Friedman said security at Los Alamos was "seriously flawed" when a worker removed classified documents later found in her home during a drug bust last month.

In a number of key areas, security policies at the nuclear weapons lab were nonexistent, not followed or were applied inconsistently, according to Friedman's summary of his investigation.

Cyber-security internal controls and safeguards were not functioning as intended, and monitoring by the lab and federal officials was inadequate, he said.

Friedman called his findings "especially troubling" because the department has spent so much money on improving security in recent years and because previous security lapses were part of the reason the department put the lab's management contract out for bid.

Since June, the lab — operated for decades by the University of California — has been run by a team comprised of UC, Bechtel National, BWX Technologies and Washington Group International.

Energy Secretary Samuel Bodman said Tuesday that the report outlines "some significant deficiencies and vulnerabilities" that the agency will quickly address.

"Unfortunately we cannot correct the errors of the past. But we will learn from this incident and we will do better," Bodman said in a statement.

The department did not release the report itself, which Bodman said contained information the department is prohibited by law from publicly disclosing.

Classified documents were found Oct. 17 at the home of Jessica Quintana, 22, a former employee of a lab subcontractor. A man who was renting a room at her home was jailed on drug and probation charges.

Quintana's lawyer, Stephen Aarons, has said the classified data was contained on a portable computer storage drive and in about 200 pages of paper documents.

Aarons says Quintana, an archivist who was converting lab documents to an electronic format, took the information home to catch up on work. He says she never showed it to anyone and there was no espionage involved.

LANL officials have said none of the material was top secret, nor did it contain the most sensitive nuclear weapons information. They said most of the documents were classified at the lowest levels and were 20 to 30 years old.

Quintana, who was laid off by the subcontractor about a month before the documents were discovered, hasn't been charged.

Lab Director Michael Anastasio said in a statement Tuesday that the lab has taken a number of security steps, including barring portable electronic storage devices in classified computing areas.

All classified scanning activities have been temporarily halted, and physical searches have been increased, with random searches occuring an average of more than 100 times daily, Anastasio said.

The lab's high-profile security problems include the case of scientist Wen Ho Lee, who pleaded guilty in 2000 to one count of mishandling nuclear secrets. In 2004, the lab was essentially shut down after an inventory showed that two computer disks containing nuclear secrets were missing. A year later the lab concluded that it was a mistake and that the disks never existed.