The Department of Energy’s National Nuclear Security Administration announced that it has successfully removed all cesium-137 irradiators from South Carolina, as the agency seeks to eliminate radiological threats and protect communities.

Cs-137 sources are commonly used to irradiate cellular blood cells prior to transfusion to prevent graft-versus-host disease, where the donated cells view the recipient’s cells as an unfamiliar threat. If stolen from a less-secure facility, however, the cesium inside the irradiators could be used to create a radiological dispersal device, commonly referred to as a dirty bomb.

Kansas is now one of 11 U.S. states and territories that are free of cesium-137 irradiators—the others being Alaska, Arizona, Delaware, Idaho, Iowa, Nevada, New Mexico, Puerto Rico, South Dakota, and Wyoming. The Department of Energy’s National Nuclear Security Administration announced on September 10 that it had completed the removal of all of these medical devices from Kansas as part of its ongoing effort to reduce radiological threats in the United States.