The Defense Department, which is responsible for the largest anthrax breach in history, finally came up for a reason behind it.

No top Pentagon official was responsible but rather “procedures were the primary culprit.”

The Defense Department said the leak was an Army mistake, even as it conceded that Pentagon officials failed to set standards for killing anthrax or take action when it first became clear one lab was failing to properly test its anthrax.

The report found that at least one DoD lab sought to kill live anthrax in an unusually large batch size and then applied inadequate radiation doses to inactivate live spores. Since 2003, that lab, Dugway Proving Ground, mistakenly sent out live spores around the world 50 percent of the time. But the report and DoD officials refused to say who came up with those protocols.

Dugway failed to use enough radiation to kill anthrax and it did not correctly conduct subsequent tests to confirm the anthrax was dead. In footnotes throughout, the report dwells on how difficult it is to kill anthrax, but no one would explain why, if it is so hard to kill, DoD allowed one lab to use minimal protocols.

Rather, “we were shocked by these failures,” said Deputy Secretary of Defense Bob Work, even as he refused to explain how those protocols came to be in place. “It was absolutely inexcusable.”

The Daily Beast first reported on the findings this month.

Experts said it appeared DoD was sidestepping a major failure and that establishing a protocol is a function of basic math. All one must do is estimate how many spores are in a batch and then read off a graph to find the amount of radiation needed. Under the figures DoD provided, the Army left as many as 10,000 live spores in each of the 149 batches Dugway claimed it had properly inactivated.

Even then, if DoD had performed quality control testing properly, it would have seen that live anthrax spores remained, experts said.

“They had a job to produce this, and they ignored safety standards,” said Richard Ebright, professor of chemistry and chemical biology at Rutgers University. “They knew from their own results, even with their own flawed quality testing, that it was failing.”

On Thursday, the department presented its findings in what it called a “comprehensive review” that was supposed to answer how the U.S. military mistakenly sent live anthrax spores to 86 labs around the world—in 21 states, D.C., and seven nations—for use in developing detection and decontamination methods.

Work, Frank Kendall, the Under Secretary of Defense for Acquisition, Technology and Logistics, and other DoD officials refused to explain why their labs used such unsafe standards.

The reports suggested that officials realized years earlier that attempting to kill anthrax in such large batches with such minimal standards was not working. The DoD officials refused to say why the protocols were not adjusted or who made the decision to keep using them.

Indeed, it is possible officials at Dugway even lied to those conducting the report.

Kendall said when investigators asked Dugway about their failure rate, officials there said it was 2-3 percent. When investigators reviewed the records, they found a 21 percent failure rate, or what DoD tried to explain away as a “simple misunderstanding.”

Officials already privately suggested that there were no plans to close Dugway but rather that some commanders could lose their jobs. The U.S. Army has been tasked with conducting a formal investigation into determining who, if anyone, was responsible. The initial DoD report found there was no single human culprit outside the Dugway chain of command.

"Secretary McHugh was deeply troubled by the report's findings, and immediately ordered that a corrective plan be developed, and a 15-6 [formal military] investigation be conducted to determine whether there were any failures of leadership. We will work with the Department of Defense and the Department of the Navy to ensure that all our labs are safe, secure and in full accordance with all regulations, policies and proven scientific methods and procedures,” Army spokesman Col. David P. Doherty said in a statement.

Kendall said there was no major difference between protocols at Dugway and the other three DoD labs that inactivate anthrax, but did not explain why officials were not examining the remaining facilities. The officials suggested once they institute new protocols, the problems will be mitigated. Work went on to say there was nothing reckless going on in the labs.

Ebright, however, called it “criminally negligent.”

To be sure, there are no federal standards for how to kill live anthrax spores, leaving the DoD to come up with their own procedures. There is no standard because the Centers for Disease Control and Prevention has consistently refused to set them. And so the individual institutions, like Dugway, have crafted their own.

The DoD has said it now will set a standard protocol for all its facilities. But many think the DoD needs to stop sending out anthrax to other labs.

“There is no legitimate military or civilian purpose that requires inactivated anthrax from fully virulent strains,” Ebright said.

Dugway Proving Ground, about 85 miles southwest of Salt Lake City, first learned it had shipped activated anthrax spores when a private lab in Maryland notified the base on May 23. The Maryland lab then informed the CDC, which is leading the investigation.