Students were evacuated and a 15-year-old was taken to a hospital after reports of fumes making students sick at Rancho Bernardo High School, according to San Diego Fire and Rescue.
The fumes were reported in the science building at about 8.40 a.m. Thursday, said San Diego Fire and Rescue spokesperson Maurice Luque.
Authorities say 237 students were held in the football stadium for approximately 90 minutes until environmental health officials gave the all clear.
A 15-year-old girl was taken to a local hospital as a precaution, Luque said.
Authorities think the fumes may have drifted into the school from a leaf-blower that was being used outside one of the classrooms.