Nitro, WV – Classes were canceled at Nitro Elementary Wednesday due to an issue with a heating unit.

Terry Hollingsworth, director of maintenance, tells WSAZ they discovered a crack in the school’s heating exchange releasing carbon monoxide in the building.

The gas was immediately turned off in the building until they determined what unit had the crack.

The issue was discovered before students arrived at the school. Kanawha County Schools canceled classes just before 7 a.m. Wednesday.

No one was allowed in the building until crews gave the all clear.

All of the doors at the school were opened all day and fans were on trying to air out the building.

Hollingsworth says the unit is being repaired Wednesday and classes will resume on Thursday.

The Nitro Fire Department responded and assisted with the situation.