A monthlong Pentagon investigation could not identify a root cause as to why an Army testing facility in Utah mistakenly sent live anthrax samples to 86 commercial companies, academic institutions and federal laboratories around the globe.

The Pentagon released a report Thursday signed by a review committee made up of 21 scientific professionals that said all U.S. military personnel correctly followed protocols in which the samples were supposed to be rendered dead through irradiation.

“There is no single root cause to explain why the [anthrax] samples were incompletely inactivated, or why viability testing did not detect live [anthrax] spores,” the 38-page report said.

The report found some deficiencies in the established protocols -- for example, it said there was the potential for live spores to contaminate the dead samples, and protocols were not standardized across all labs. The testing may have failed to find live spores because sample sizes were too small or incubation periods too short, it said.


The investigation also revealed that over the last decade, the Army facility has shipped “low concentrations” of live anthrax samples to 86 facilities in the U.S. and seven other countries, according to the report.

“The low numbers of live spores found in inactivated DoD samples did not pose a risk to the general public,” the report read. “Nonetheless, the shipment of live [anthrax] samples outside of the select agent program restrictions (at any concentration) is a serious breach of regulations.”

The accidental transfer did not cause any infections, though at least 26 people were treated for possible exposure after the problem was uncovered in May. The Pentagon and the Centers for Disease Control and Prevention launched an investigation May 22, after a lab in Maryland cultured an anthrax sample from the Army’s Dugway Proving Ground facility in Utah and discovered live spores of the deadly bacteria.

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The shipments of Bacillus anthracis, the bacterium that forms anthrax, were sent without proper safeguard to labs in 20 states and the District of Columbia, the Defense Department said. Shipments also reached labs in Australia, Britain, Canada, Germany, Italy, Japan and South Korea.

Dugway is an isolated military facility in the desert of southwest Utah and is said to be as large as Rhode Island. Scientists there develop and test U.S. and allied defense systems against chemical and biological weapons.

Under normal circumstances, officials have said, scientists use gamma radiation to render anthrax inactive, then place the sample in an incubator for 10 days and make sure the spores did not multiply. At that point, each sample is given a “death certificate” and then frozen.

Anthrax is not contagious but can be inhaled, ingested or transmitted through contact on the skin. Someone who is infected may not show symptoms for weeks.


Infectious-disease professionals say anthrax is the most likely biological agent to be used in an attack because it is widely available.

Hennigan reported from Washington. Queally reported from New York.

Follow @JamesQueallyLAT for breaking news.

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