US media WCMH-TV reports the incident happened on Wednesday evening (local time) at the Ohio State Fair in Columbus.
It’s reported up to seven people have also been injured, five are considered to be in critical condition.
The Ohio State Fair has confirmed the incident on Twitter.

A photo taken at the entrance of the Ohio State Fairl. Source: Ohio State Fair/ Facebook
Footage of the incident uploaded to YouTube showed seats break off from the ride and crash into the ground.
A person can also be seen being thrown from the ride while it is in motion.
Witnesses told NBC part of the ride went "flying off".
Rhonda Burgess said she and her three children were at the fair.
"The ride had five riders per cart. This piece snapped off and the riders came out of the cart," she said.
"At least two (people) flew threw the air at least 20 feet before landing on their backs on the concrete."
Ohio Governor John Kasich said he was “terribly saddened” by the incident.
He has ordered all rides and attractions at the fair to be shut down until inspections have taken place.
The fair is scheduled to run until August 6, the incident happened on the event's opening day.