Wentworth school in Scarborough was evacuated Thursday morning and nearly a dozen students were taken to the hospital after they reported feeling sick.
Scarborough Fire Chief Rich Kindelan said the school was metered for a possible gas leak, but revealed no hazards.
"There was no real reports of a particular smell so that's why we metered it for several different gasses to make there was nothing present," Kindelan said.
Superintendent Diane Nadeau said students were rehearsing for a concert on stage in the school cafeteria when one student passed out on the risers, and others began to make complaints of respiratory discomfort.
By 12:30 p.m. Thursday afternoon, students and staff were allowed back in to resume classes.
All 11 patients were treated and released from the hospital, according to a spokesperson for MaineHealth Maine Medical Center.
