East Elementary in Cheboygan was closed for a third day Thursday as they continued to investigate what caused some staff members and students to feel sick on Monday.
Superintendent Spencer Byrd said an odd smell that some described as smelling like diesel or wire burning was noticed on Monday.
By afternoon, staff and students complained of headaches, burning eyes, and nausea.
One staff member even went to the hospital to get checked out.
The school was closed Tuesday through Thursday as they investigated further.
Byrd said the cause is still a mystery.
They thought it might have been carbon monoxide poisoning but he says their CO levels were not elevated.
Byrd did have a theory on what might have caused it.
“We had a lot of snow over the weekend. So, one of our custodians was using a diesel tractor to push the snow, clear the sidewalks. And potentially what was happening is as he was driving down those sidewalks and clearing them. He was blowing in exhaust, near the ventilators that were supposed to be bringing in fresh air [and] was possibly bringing in exhaust from a diesel tractor,” said Byrd.
He said they may never know the cause, but they have brought in the environmental agency Nova and a building inspector to give them the go-ahead to reopen once they are confident it is safe to do so. At an afternoon meeting that stretched into the evening, they decided to open school on Friday.