Technical Lab Manager Barbara Murphy inspects a refrigerated storage cabinet at the laboratory of Cell biology at NIH in Bethesda, Md. in July. Investigators have finished a sweep of federal labs that began after vials containing smallpox were found on NIH’s campus. (Bill O'Leary/The Washington Post)

Investigators poring through thousands of government labs turned up another two dozen potentially dangerous biological materials that were not properly accounted for, including the toxin ricin and a deadly form of avian flu, during a far-reaching inventory this fall, according to documents released Tuesday.

The findings are part of an unprecedented accounting of federal laboratories that began after long-forgotten vials containing smallpox were found this summer at a Food and Drug Administration lab on the campus of the National Institutes of Health. That discovery came amid a series of other lab safety lapses, including an incident in which scores of workers at the Centers for Disease Control and Prevention were potentially exposed to live anthrax.

Collectively, those security shortfalls “really caught our attention here at the White House,” an administration official who was not authorized to speak publicly about the findings said Tuesday.

The result was a months-long sweep that involved nearly a dozen federal agencies, 4,000 lab facilities from Arkansas to Alaska and more than 40 million biological samples.

In September, as the massive inventory was underway, officials disclosed that they had found half a dozen improperly stored substances, including ricin and the bacterium that cause plague.

On Tuesday, officials said the additional materials they discovered in the last weeks of the search included vials of virulent bird flu at Agriculture Department labs in Iowa and Georgia, as well as samples of the bacterium that causes botulism, found at a CDC lab. Those samples were destroyed. Some others were transferred to labs authorized to house them.

Government officials were quick to note Tuesday that the samples, while not properly registered with authorities who oversee dangerous “select agents,” were all stored safely and that there was no evidence suggesting that employees or the general public were in danger of being exposed to them.

Rather, they said, in some instances the samples had been stored in certain labs decades earlier, before they were deemed select agents that required heightened regulations. Also, many labs traditionally have lacked reliable inventory systems and have not always tracked biological samples that remain after researchers retire or move on.

Federal officials said Tuesday that the smallpox discovery this year, along with other incidents, has prompted a move toward better accounting and safety protocols throughout government labs.

For instance, the FDA, the CDC and NIH, among other agencies, have vowed to put in place new inventory monitoring systems aimed at keeping tabs on the potentially dangerous pathogens in government labs, as well as who has responsibility for each sample. Numerous agencies have also begun considering how to update and strengthen their training and security protocols to try to rectify what CDC Director Thomas Frieden has called “an insufficient culture of safety” in some labs.

The issue gained national attention over the summer when as many as 84 CDC workers might have been exposed to live anthrax after employees unknowingly sent samples of the bacterium from one CDC lab to other CDC labs. The agency later acknowledged other lapses, such as the fact that one lab mistakenly sent a sample of flu virus contaminated with the deadly H5N1 influenza virus to a USDA lab in Georgia.

Weeks after the anthrax incident, a government scientist cleaning out a cold-storage room at an FDA lab on NIH’s Bethesda, Md., campus found decades-old samples of smallpox. The vials containing the deadly virus, which was eradicated decades ago after killing hundreds of millions of people, were dated from 1954.

Alongside the smallpox samples, officials discovered hundreds of vials of other pathogens, including the virus behind the tropical disease dengue and the bacterium that can cause spotted fever.