The ride combines a swinging and spinning motion, flinging people back and forth through the air and around in circles.
One of the people treated at the scene was a child under the age of 13.
Video posted online shows people being thrown from the ride after a bench snapped off at the bottom of a swing.
Columbus Fire Battalion Chief Steve Martin confirmed the injuries and the death on Wednesday night, WCMH reports.
Wednesday was the opening night of the fair, which is scheduled to run until August 6.
The fair confirmed something had been reported, tweeting: "There has been a report of a ride incident. We are investigating and will report information as available."
One witness who saw the incident posted a video on Instagram, along with the caption: "Sad Day here at the Ohio State Fair... Lord help their families".
Ohio Governor John Kasich released a statement Wednesday evening, reading: "I am terribly saddened by this accident, by the loss of life and that people were injured enjoying Ohio's fair.
"Our thoughts and prayers go out to those grieving and injured. I have ordered a full investigation into this incident and have ordered that all fair rides be shut down until additional safety inspections can be completed."
The incident comes after ride inspectors from the Ohio Department of Agriculture were forced to work long hours this week to make sure everything was up to standard, due to delays caused by heavy rain in recent days, the Columbus Dispatch reports.
"The rain slowed us down a little bit. Usually a lot of this stuff would be up a lot faster," Ron Dean, an amusement ride inspector who has been with the Ohio Department of Agriculture for 13 years, told The Dispatch.
The fair is celebrating its 164th year in 2017.
