Multiple police cruisers were on scene, along with a Dayton ambulance.
Parents were seen coming to the library to try to find their children after the evacuation.
The library reopened to the public a little before 5 p.m.
Dayton Metro External Relations and Development Director Debi Chess declined to comment on the details of the incident, but said the library always keeps the safety of its patrons in mind.
We have reached out to Dayton police for more and will update this story with any new information.
