More than 7,000 Americans go to the emergency room every year after getting injured on carnival rides, the federal government estimates.
Here's the issue: The Consumer Product Safety Commission regulates how the rides are manufactured, but there is no federal oversight over how they are set up and maintained.
That's left to the states, and some do a great, thorough job, but others do nothing.
CLICK HERE to see how and how often your state inspects carnival rides
Carnival rides are supposed to be a little bit scary, not a lot. But terrifying accidents happen every summer for three main reasons: equipment failure, inconsistent state regulations and old-fashioned human error.
Earlier this month in Pleasanton, Calif., a thick bicycle-style chain on a kids' roller coaster snapped, whipping riders as they passed by.
"I saw that someone was getting taken by ambulance and had her neck all wrapped up and she couldn't move it," witness Nadine Cobb said at the time.
Seven people were injured.
"It was very challenging in the beginning, because they were covered in black grease," Alameda County Fire Department assistant chief Alan Evans said.
The preliminary diagnosis: a defective cable.
"Like any piece of machinery with moving parts, there are external failures and there are internal failures and ... despite the fact that we wish we all had X-ray vision, we cannot always spot those internal failures," said Ken Martin, an amusement ride safety consultant.
Martin has 20 years of experience inspecting carnival rides. He said the machines are well built, but the breakdown occurs -- literally and figuratively -- in how states inspect them.
"Some states enforce rules one way, others enforce rules a different way," he said. "Some states even allow the owners to inspect the rides themselves."
Some states inspect carnival rides every time they are set up in a new location, others only inspect them once a year. And six states perform no inspections whatsoever, according to the Consumer Product Safety Commission.
"The best thing for the amusement ride industry would be a uniform set of regulations that are applicable in all 50 states." Martin said.
Even if the equipment is in good shape, operator error is the next variable. At an Indiana festival in May, two girls were injured on a ride that included a plunging drop. Authorities said the operator accidentally released the safety catch on the cage the girls were in and it opened.
And then there is the third factor: the human element. A fair worker's leg was severed last month after the worker was struck by a small roller coaster in Petaluma, Calif.
"It was all kind of gruesome," witness Esaia Gonzalez said. "So you know we glanced then looked away."
The carnival operator said the worker was not in charge of the ride and had no business being in the area.
"He would have to literally walked over to the ride, removed a piece of the fence panel, stepped inside the ride," said Harry Mason, CEO of Midway Fun, which operates the rides at the fair. "There was a lot of effort."
Virginia and other states have passed rider responsibility laws that require carnival guests to behave on rides. Martin said our responsibility begins long before that.
"You, yourself, before you get on that ride are the final inspector," he said. "If it looks bad, it probably is. If it sounds bad, it probably is."