The incident happened at the New Haven Public Schools on the morning of Thursday, May 19, in a classroom at Wexler-Grant School, according to a NHPS representative.
The students and teachers were taken to Yale New Haven Hospital to be checked out after experiencing symptoms of an "airborne irritant," officials said.
The New Haven Fire Department found evidence that a cubicle in the classroom had been contaminated with a defensive spray, such as mace, the district reported.
Officials said the classroom is being cleaned and vented.
Following the incident, students were evacuated to the Q-House next to the school, while the cause of the issue was being investigated, the district said.
Officials said the students were set to return to other classrooms in the school and be dismissed at the regular time.
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