A group of 69 military personnel returned to Ft. Bliss, Texas on Tuesday following a deployment in West Africa and are now under a mandatory 21-day quarantine, the Pentagon said Wednesday. One of the service members is being closely monitored for potential Ebola symptoms.

The service member “threw up” on the plane ride back to the U.S., said Pentagon spokesman Col. Steve Warren, who was unable to detail any of his symptoms.

In an off-camera briefing at the Pentagon, Warren told journalists, “Don’t panic.”

“Of the group that came back yesterday to Ft. Bliss one person did appear ill,” he said. “We are taking all the appropriate measures.  So far nothing more than that, it could have just as easily been air sickness.”