Three people were hospitalized today after they developed “rash-like” symptoms when handling a suspicious package in the mail room this morning at Scott Air Force Base in Illinois.

A spokesman for the base said the individuals have been treated and released.  Parts of the base, which is located about 25 miles east of St Louis, Missouri, remain under evacuation as a precaution.

“Scott AFB emergency responders are well-trained professionals who provided immediate response. They are working diligently to render the area safe and investigating the source of the package,” Col. Mike Hornitschek said in a statement.

The three servicemembers were transported to Memorial Hospital for “possible chemical exposure.” Another 13 people are being decontaminated on site. Those treated on site have also been released.

Base officials say they still do not know what the package contained, but said it is being currently tested. A spokesman was unable to describe its contents but said there is “no immediate threat to the community.”