18 students and one teacher were exposed to the nuisance spray or stink bomb.
Three students were taken to a local hospital, with two being in good-to-fair condition and the other in fair-to-serious condition, according to officials.
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The incident happened at Fairfield Elementary School in Chicago, Illinois, according to FOX 32. Ambulances responded to the school at around 9:46 a.m. after someone carried a nuisance spray or stink bomb into a classroom, according to a Chicago Fire Department spokesperson. (Google Maps)
Thirteen other students and the teacher were evaluated by first responders at the school, but declined to be taken to the hospital.
Ambulances took the students taken to a local hospital out of largely "precautionary" measures, officials said.