Seven people were placed in a short time after a suspicious package with “a white powder” was sent to the united Andrews in Maryland, on Thursday.
According to a spokesperson for the base, someone opened the package sometime in the afternoon, and it was cleared in the early evening.
All those who became ill have since been released from the hospital – and the details of the powder, or the diseases it can cause, are unclear at this time.
“The joint base Andrews responded to an incident here today after an individual opened a suspicious package. As a precaution, a cordon has been strengthened around,” the base cordon said in a statement to Wusa9.
“Joint Basic First Responders Dispatched to the Scene, determined there are no immediate threats, and normal operations are continuing. An investigation is currently underway.”
CNN, which first reported the incident, said that the package contained an unknown white powder and that several people were taken to Malcolm Grove Medical Center on the basis. The extent of their illnesses is unknown.
The outlet reported that first responders from the base determined there was no immediate threat and returned the scene to the US Air Force office for special investigation.
An initial field test from the hazardous materials team did not detect anything harmful, but the investigation continues, CNN reported, citing one of the sources familiar with the matter.
CNN said the room where the envelope was opened – located in a building that houses the Air National Guard Hardiness Center – has been closed.