A swinging and spinning amusement park ride has broken apart on the opening day of the Ohio State Fair, hurling people through the air, killing a man and injuring seven others.
Three of the injured were in a critical condition, authorities said.
"The fair is about the best things in life and tonight with this accident it becomes a terrible, terrible tragedy," said Ohio governor John Kasich.
The man who was killed was one of several people who were thrown off when the Fire Ball ride malfunctioned, Columbus Fire Battalion chief Steve Martin said.
Dramatic video captured by a bystander shows the ride swinging back and forth like a pendulum and spinning in the air when it crashes into something and part of the ride flies off, throwing riders to the ground.
A company providing rides at the Columbus fair this year describes the Fire Ball as an "aggressive thrill" experience.
On its website, Amusements of America says that since its debut in 2002, the Fire Ball has become "one of the most popular thrill rides on the AOA Midway".
The company description of the ride says it swings riders 40 feet above the midway while spinning them at 13 revolutions per minute.
Mr Kasich said he had ordered a full investigation and all fair rides to be shut down until additional safety inspections can be completed.
In a post on its Twitter page the fair said: "There has been a report of a ride incident. We are investigating and will report information as available."
The Ohio State Fair runs until August 6.
State director of agriculture David Daniels said all the rides were checked several times when they were being set up to ensure it was the way the manufacturer intended.
"We started out today with 11 rides that did not open because the inspection work was not done on them," he said.
Mr Daniels said four rides would not be operating because they did not meet the mechanical test.
Ride inspectors said the Fire Ball was inspected at a couple of different stages and signed off Wednesday.