A medical phenomenon in which a number of people show real illness symptoms when no real cause exists is now suspected at the school in Springfield, Minnesota, where 30 went to the hospital Thursday, FOX 9 reports.
FOX reports the state health department says it was a case of "mass psychogenic illness" at the K-12 public school building – a mass reaction when lots of people in a shared space end up sick without a specific cause, except the fact that everyone in the group shares the same belief about the cause, according to the National Institutes of Health.
Despite the FOX report, health department spokesman Scott Smith told BringMeTheNews Friday morning it was too premature to definitively say the event was mass psychogenic illness.
"It's a possibility that is being considered, but the investigation is still ongoing," he said.
Carbon monoxide was initially suspected at the Springfield school Thursday morning after some elementary school students got sick in an auditorium during a choir rehearsal. Several students were promptly taken to the hospital and the school's 600 students were evacuated.
By the end of the day, 30 students had been treated and released at the hospital, a Mayo health facility in Springfield, after they suffered symptoms including nausea and headaches – common symptoms of carbon monoxide poisoning.
The Mankato Free Press initially had reported lab tests indicated some patients had higher than normal levels of carbon monoxide in their blood. But hospital Administrator Scott Thoreson on Friday told the Free Press that more thorough lab tests indicated normal levels.
And in fact, the Free Press and New Ulm Journal reported that officials detected no carbon monoxide in the school building during the day Thursday and Friday.
School was canceled for students Friday as the investigation continued.