The emergency room at Hoboken University Medical Center was briefly shut down Thursday after a teen allegedly brought a homemade bomb into the building.

A mother reportedly brought her son into the hospital after she noticed he was working on a project in his room. According to hospital spokesperson Joan Quigley, that project contained turpentine and spark plugs. Quigley says the mother gave the device to a nurse, who called the bomb squad.

The emergency room was shut down for 90 minutes during the incident. The 15-year-old is undergoing a psychiatric evaluation.