UPDATED: 10/7/2013 – 11:10 a.m.

CHICAGO (CBS) — Classes were cancelled at a South Side elementary school on Monday, after a fire damaged two classrooms before students arrived.

CBS 2’s Mike Puccinelli reports a custodian smelled smoke around 6:45 a.m. at Oglesby Elementary School, at 7646 S. Green St. in the Auburn-Gresham neighborhood. The custodian spotted flames in a classroom, and called 911.

When firefighters arrived, they found a science classroom on the top floor of the building engulfed in smoke and flames. Investigators said the fire appeared to be electrical in nature, and might have started in the ceiling of the classroom directly below the one that burned.

One of two school employees who were in the building at the time said she did not hear a fire alarm.

“I was in the kitchen, so I just happened to be worried about my co-worker, came to the door, and saw the flashing lights. I never knew it was a fire, because I’m in the basement,” she said. “The alarm didn’t go off.”

Classes were cancelled after the fire, to allow crews to air out and clean the damaged classroom, though several students showed up for school before getting word that school was out for the day.

Students who showed up for school were allowed to go home with their parents, or were sent to nearby Wentworth Elementary School to attend class there.

A few hours after the fire was extinguished, firefighters were called back to the scene, when a hotspot flared up. That prompted officials to evacuate the staffers and students who were in the building at the time, waiting for school buses to take students to Wentworth.

No injuries were reported, though two classrooms were heavily damaged by smoke, fire, and water.

And for a mother of four Oglesby students, the fire meant scrambling for childcare.

“My sister’s going to be watching them,” said Charnell Gates. “She’s going to give them some school work, and I’m going to see what’s going on with the school.”

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