The administrative building of the National Institutes of Health in Bethesda, Md. (J. Scott Applewhite/Associated Press)

As news was breaking Tuesday about the discovery of decades-old vials of smallpox virus in a building on the sprawling Bethesda campus of the National Institutes of Health, NIH officials reached out to Montgomery County officials and telephoned Maryland health officials. Senior NIH executives also were alerted.

But no general notification was sent to the 18,000 NIH employees who work at the main campus of the nation’s medical research institution, according to the agency. One researcher said Wednesday that some employees thought they should have been told, even though there was no evidence of infectious-exposure risk to workers or the public.

“I think the responsible thing to do would have been to inform us without us having to find out through the media,” said the researcher, who works at the clinical center on the main campus and did not want to be identified for fear of retaliation.

In 2011, a deadly infection untreatable by nearly every antibiotic spread through the NIH clinical center but was not made public until a year later, when researchers published a scientific paper about how they had traced it. NIH pledged to do better about informing local and state officials about high-profile diseases or outbreaks, even those that do not pose an obvious public risk.

In the case of the smallpox discovery, an NIH spokeswoman said the agency did not notify employees because the vials were secure and did not present a safety concern or threat. The directors of the NIH’s 27 institutes and centers were informed Tuesday morning.

This 1975 electronmicrograph shows the smallpox virus. (Centers for Disease Control and Prevention via AP)

The FBI and the Centers for Disease Control and Prevention in Atlanta are investigating how the smallpox samples were prepared and stored in the building. The CDC sent an e-mail to all employees and contractors midday Tuesday informing them of the discovery, about the same time that it alerted media.

“We’ve learned that you simply can’t overcommunicate when it comes to an event like this,” said CDC spokesman Tom Skinner.

Last month, live anthrax bacteria was released accidentally at CDC labs in Atlanta, resulting in as many as 84 employees getting vaccines or antibiotics as a precaution and a lab director being reassigned.

CDC employees working in labs adjacent to the affected areas complained at a staff meeting that they “wished we would have known what was going on sooner,” Skinner said. CDC Director Tom Frieden later apologized in an e-mail for the delay in informing the wider CDC community.

The Food and Drug Administration, which has authority over Building 29A, where the smallpox samples were found July 1, notified its workers. By July 2, about a dozen FDA employees working in labs immediately adjacent to the cold-storage room where the vials had been found were informed, an FDA spokeswoman said.

Building 29A is one of several labs the FDA has been operating on the NIH campus since 1972. The vials were discovered while employees were preparing for the lab’s move to the FDA’s main campus in White Oak, Md. The labs where the smallpox was discovered are used for biologics research, including research on vaccines. The vials were in a third-floor room that was kept at about 40 degrees.

Shortly before 8 p.m., about seven hours after news reports of the incident Tuesday, FDA Commissioner Margaret A. Hamburg sent an e-mail to all FDA employees.

“This is quite an unexpected and unusual incident,” she said in her e-mail. “I want to assure all FDA employees that we are taking immediate steps to further ensure the safety of our laboratories and our staff.”

An inventory of all common storage areas in NIH campus buildings has found no other materials of concern, FDA officials said.

It’s likely that an investigator involved in smallpox research, prior to when smallpox was declared officially eradicated in late 1979, left the boxes in the cold-storage area, FDA officials said. The regulation of vaccines, including smallpox vaccine, was under the authority of the NIH until July 1972, when it was transferred to the FDA. At that time,the laboratories on the NIH campus were transferred to FDA as well.

Sixteen vials were flown Monday to the CDC in Atlanta, one of just two locations in the world where smallpox is allowed to be stored. Initial testing confirmed the presence of smallpox-virus DNA. Further testing, which could take up to two weeks, will determine whether the material is live. The samples will be destroyed after the testing is completed, CDC officials said.