A summer amusement turned into a serious nightmare on Sunday, after a roller coaster malfunctioned in midair, trapping eight passengers upside down for several hours.

The oscillating Fireball was just sliding down from its vertical loop at the Forest County Festival in Crandon, Wis., when it stopped unexpectedly because of a mechanical failure, according to a joint press release from the local fire department and rescue squad.

Emergency personnel were dispatched to the scene within 15 minutes but needed to request special equipment, including three ladder trucks, from nearby towns to complete the rescue. One truck with the capability of rising over 100 feet took approximately 45 minutes to arrive on the scene.

An off-duty firefighter with specialized rope rescue training happened to be at the festival at the time of the incident and advised the local crews on possible options.

"Due to the release mechanism of safety equipment on individual cars, all individuals in a car needed to be properly secured prior to release of safety equipment," the fire department said.

The complexity of the operation meant that the first of the passengers was not safely back on solid ground until 3:20 p.m. CT, roughly two hours after the ride had first gotten stuck. It took another hour and 40 minutes for all remaining passengers to be rescued.

Videos posted to social media show carnival workers grinding on metal, desperately trying to unstick the coaster as firemen on ladders talked calmly to the suspended passengers.

Scott Brass, a carnival-goer who watched the rescues unfold, told NPR in a social media message that five of the passengers appeared to be children.

One of them, a girl, told the rescuers to unstrap an older man first because he was visibly struggling and appeared to have passed out at one point, Brass recounted.

"That little girl deserves a medal of courage for sure," Brass said.

Once on the ground, the passengers were offered treatment by teams from a total of nine ambulances. One patient was transported to a nearby hospital, the fire department said.

The cause of the ride's mechanical failure is still unclear. The operator told local rescue crews that the ride had been inspected on site by state authorities, as is standard safety procedure.

The incident unfolded just days after a 325-foot-tall roller coaster in North Carolina was closed for ominous-looking repairs. Visitors to the Carowinds amusement park had reported seeing a fissure in one of its steel support beams, which caused the beam to shake and sway as cars took a sharp turn at top speed. [Copyright 2023 NPR]