The incident happened around 9:40 a.m. at the Joseph H. Brown School in the 3600 block of Stanwood.
Fire crews and medic units were called in after children became sick after smelling fumes that officials say came from a faulty generator that started after the school lost power.
Fifty-three students had to be taken to five area hospitals to be treated for nausea and dizziness.
Other children were evaluated at the scene.
Distraught parents arrived to the school to check on their children. Nearly 600 students had been evacuated from the 3-story building.
Many parents decided to take their kids home.
Authorities from the Fire Department initially said carbon monoxide was detected, but the reading turned out not to be high.