Twelve students from Eastbury Elementary School in Glastonbury were taken to Connecticut Children's Medical Center Thursday morning because they got sick in school.
Hospital staff said it appears they were overheated because of a hot cafeteria and the superintendent said it appears the ventilation system in the cafeteria was not working.
The fire alarm went off after one student fainted and several others started getting sick, including get nauseous or vomiting. A student who NBC Connecticut spoke with said the incident happened during a chorus class in the cafeteria.
The school at 1389 Neipsic Road was evacuated as a precaution.
In all, 12 students were transported for medical treatment, including one who fainted.
Dr. Steven Rogers, of Connecticut Children's Medical Center, said they were concerned about possible chemical exposure, including to carbon monoxide, but also considered the possibility that the illnesses could be heat-released.
Firefighters said they checked the building, but did not find anything hazardous.
Rogers also said they didn't detect high levels of carbon monoxide when they evaluated the patients and everyone they've treated is doing well and has been discharged.
The students became ill on a day that was not terribly hot and Rogers addressed how they might have become sick.
"So you can imagine, without good ventilation, just like your car can heat up to well over 130 degrees in a matter of minutes, so can a classroom without good circulation," Rogers said.
He reminded parents to ensure that children go to school in the appropriate clothing during hot weather, and they are well hydrated and have access to water throughout the day.
Supt. Alan Bookman reached out to parents and said some students felt faint at school and school officials contacted parents.
Bookman said it appeared the ventilation system in the cafeteria was not functioning and that led to the students becoming overheated.
The school was closed for the remainer of the day and parents were able to pick up their children at Gideon Welles school.