When a carbon monoxide (CO) incident happens on a school campus, one of the first questions everyone asks is: “Where did it come from?” Parents want to know. Staff want to know. Journalists want to know. Fire marshals and investigators need  to know. But right now, the language we use to describe CO sources in schools is inconsistent and confusing. News stories call it a “gas leak,” a “ventilation problem,” an “equipment issue,” or simply “fumes,” even when the actual hazard