About 20 Massachusetts children attending a Sunday church school session were sent to the hospital after authorities discovered a gas leak at St. Mary's Religious Education Center had sent carbon monoxide levels soaring.
Waltham fire officials said they responded to the gas leak Sunday morning after children and staffers complained of dizziness, Michael Quinn, the deputy fire chief, said to The Boston Globe.
Testing revealed that carbon monoxide levels were "extremely high," authorities said, United Press International reported.
The children, all between ages 8 and 12, were sent to the hospital, Chief Quinn said.
"A lot of it was precautionary," he said, UPI reported.
Meanwhile, the building was evacuated and fire officials shut down the heating system to investigate the source of the leak.
About 50 children and a few teachers were in the building at the time of the leak.
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