Authorities were called to the scene at 12.05am and firefighters were met with employees exiting the building of Yenkin-Majestic Paints, ABC News reported.
Five people were taken to hospitals in the area for treatment but were in stable condition, Columbus Fire Battalion Chief Steve Martin said.
He added: “Two other employees were trapped inside the building and had to be rescued. They are in critical condition at OSU Main.”
Chief Martin later told 10TV that the explosion triggered a large fire and that the two individuals who were taken to hospital in critical condition are now stable.
All of the injured individuals are expected to survive. They are all employees at the manufacturing plant.
At 5:15am, the Columbus Division of Fire wrote on Facebook that the situation was “contained”.
“There will still be visible black smoke rising from the original fire building as we let some of the products burn off. We still have one person not accounted for, but we have been through all of the building,” the department added.
The cause of the explosion and subsequent fire is under investigation. Hazmat crews were called to the scene as the plant contains dangerous materials. Evacuations were started of nearby business buildings.