Westland High School re-opens Tuesday morning after students missed a week of classes because of an odor that sicken more than a dozen people. WOSU reports the source of the odor remains a mystery. Despite extensive testing by government agencies and private companies, investigators still donât know the source of the odor. South-Western City School officials say technicians tested the schoolâs boiler, the chiller, the air regulation system. They looked for carbon monoxide, carbon dioxide, sulfur, chlorine, fine particulates. The list goes on. Superintendent Bill Wise said everything was either negative or within normal levels. âNone of the testing has shown a presence of any substance that should cause concern," Wise said. The mystery odor, which was described as having a chemical smell and leaving a metallic taste in some peopleâs mouths, caused more than a dozen students and teachers to be treated at area emergency rooms last Monday and Tuesday. Wise said school officials are not ruling out that a student brought something to school. âIt is plausible that there was an outside element that introduced this. That is definitely a possibility and weâll continue to follow through on that until we can eliminate that as well," he said. Shawn Ansbro is an environmental specialist who helped in the investigation. Ansbro said itâs relatively common to test a site experiencing what he calls a âphantom odorâ? and find absolutely nothing. âFrom time to time weâll get calls theyâve got an odor complaint or an issue, and we frequently go out and do a very similar investigation and do what could be there and then go through and literally prove the negative that itâs not there," Ansbro said. Wise said they will continue additional tests.