The incident began about 8:30 a.m. at Finch Elementary School in southwest Atlanta, The Atlanta Journal-Constitution reported.
Police received reports of "children fainting in building," and when officers arrived at the scene, they found four students and two teachers had passed out. All regained consciousness after being removed from the affected area of the building.
A total of 25 people -- at least 12 of which were students -- were taken from the school to local hospitals for treatment, Atlanta fire Capt. Marian McDaniel said.