Students had an unexpected day off Tuesday when the first day of classes was canceled at Notre Dame High School. But classes will be held today.

Classes were scheduled to begin Tuesday morning, but administrators announced the cancellation the night before. Sister Mary Ann Fischer, principal, said classes were called off after school administrators discovered that asbestos in a small area of the building may have been disturbed while a back flow preventer was being installed on Monday.

Fischer said the asbestos in the school is contained as required by the Environmental Protection Agency and is not dangerous. However, she said, classes were canceled until EPA tests could be conducted to ensure the safety of students and teachers.

The results of those tests were in late Tuesday night. She said the tests determined the air is safe and a full day of classes will be held today.

School business manager Robert McGahan said the back flow preventer was needed to prevent the school's drinking water and water from the fire sprinkler system from mingling. The back flow preventer prevents contamination of drinking water in case the school's fire system is activated, he said.

McGahan said the sprinkler system has not been used in decades and the water sitting in the system is old. Bacteria may have formed in that water that could be hazardous if drunk.

It is likely that no health hazard ever existed in connection with the asbestos. However, McGahan said, the precautionary measures used protected the physical and mental wellbeing of people who would be working in the building.

"We don't think the asbestos was disturbed; this was just done for preventative maintenance," he said. "We didn't want to put the kids or anyone else at risk, which is why we canceled school."