First responders and police were dispatched to the school shortly before 10 a.m.
The child fell two floors down the shaft, landing safely on a metal platform, according to Fort Smith Fire Department Battalion Chief Mark Talley.
Fireman Joey Sport was put into a harness and lowered down to rescue the child.
“She was crying and she was upset, but it didn’t take much to get her to hold on to me," Sport said. "So I mean I was just glad to get her out of there.”
The girl was stuck in the duct for 10-15 minutes, Talley said.
Sharon Blentlinger, the principal at Immaculate Conception School, said the toddler was with her mom who was organizing school uniforms in the attic at the time of the accident.
"She lost a shoe but other than that she’s in perfectly good health and we’re just so thankful,” Blentlinger said. “Our guardian angels were certainly at work today.”
The child, believed to be a little more than a year old, was taken to a local hospital as a precautionary measure, according to Talley. She did not appear to be seriously injured.
The school said they're already working to close off the ventilation duct. Until it is closed off for good, school officials say they aren't allowing anyone in to the attic.