Patients and staff at Walter Reed Army Medical Center in Washington, D.C. may have been exposed to high levels of radiation, WAMU reports, because two packages of radioactive material sat under a counter in a lobby for nearly two days.

Two possible violations may have occurred, according to the Nuclear Regulatory Commission, which is investigating the incident. Walter Reed staff failed to control access to radioactive materials and failed to conduct operations so that any dose of radiation in an unrestricted area wouldn't exceed the limits in NRC regulations.

The Walter Reed Army Medical Center doesn't dispute the allegations made by the NRC, spokesman Chuck Dasey told the Associated Press Thursday.

Patients and staff may have been exposed to higher radiation than NRC allowable limits of 2 millirems in any hour, according to an NRC spokesman. The average American is exposed to 620 millirems a year.

The packages contained Thallium-201, which is used in tumor detection and cardiac studies, and molybdenum, NRC spokesman Neil Sheehan told FierceHealthcare. "It was clearly marked," Sheehan said. "It was a Saturday. Maybe staff were not properly trained, but they did not handle this material the way it should have been handled. The reality is that this shouldn't have occurred in the first place."

The packages were delivered on Saturday, May 1, to the hospital's concierge, but were not delivered directly to the facility's administrative officer, the Washington Post reports. Although the administrative officer realized that the package was missing and searched for it, hospital officials didn't find the package until Monday, May 3.

Hospital officials will give information on Walter Reed's radiation safety and nuclear medicine programs and the mitigation measures since the incident occurred in May, hospital spokesman Chuck Dasey told the Post.

To learn more:
- read the WAMU article
- here's the Washington Post article
- see the Associated Press article