(CNN) -- A malfunction at a festival swing ride in Connecticut sent children crashing into each other and onto the ground -- and raised new questions about the safety of such rides.
Families were enjoying a sunny Sunday afternoon at the Norwalk Oyster Festival when a ride called the Zumur experienced a mechanical failure that caused it to stop in mid-air, injuring 18 people, mostly children, the Norwalk Police Department said.
"It was a big boom, a big crash, three or four times over," Deyo Ello told News 12. "They slammed into the base of (the ride), and then you heard a whole bunch of screaming."
The ride -- which spins swings tethered to metal arms in an elliptical motion -- suddenly came to a jerking stop, "causing riders to collide with each other," according to the statement issued by police.
Shuan Marsh was in line at the ride when the accident happened.
"It was just injured kids everywhere. The parents ripping out the gate just trying to get to their kids," he said. "It was just horrible."
Twelve children and one adult were taken to hospitals for treatment, News 12 reported. An 8-year-old boy remained hospitalized late Sunday with non-life threatening injuries.
Stewart Amusement, which owns and operates the rides at the festival, said state officials inspected the ride Friday, two days before the accident.
"It was a mechanical failure," said Richard Stewart, president of the company. "It never happened before. We hope it never happens again. "
Stewart said his company has been cooperative with authorities, who are still investigating, and plans to have the machine taken and apart and inspected once authorities are done.
In a statement on its Facebook page, the Norwalk Seaport Association, the festival organizer, said the well-being of the children and families involved was its only concern.
The festival temporarily shut down rides after the accident but reopened them Sunday evening after fire investigators and the ride company inspected them.
"Portable rides have a very good safety record," according to amusement park safety expert Ken Martin. "In the state of Connecticut, however, they are only inspected once a year."
And that's the rub for many folk. The rules are different from state to state, with six states -- Alabama, Mississippi, Nevada, South Dakota, Wyoming, and Utah -- having no oversight at all.
Traveling rides like the one that malfunctioned in Norwalk come under federal scrutiny by the Consumer Product Safety Commission.
And they're actually inspected more than fixed rides, such as at amusement parks like Six Flags and Disney World. They fall under state jurisdiction and are often inspected by the state only when they're installed.
That's something that needs to change, in Martin's opinion.
"There is no federal oversight of fixed amusement parks and that is part of the problem," he said. "An amusement ride is an amusement ride. They need the same reporting systems, the same type of oversight, the same inspection guidelines for amusement rides all across the country."
In July, Six Flags Over Texas in Arlington shut down its Texas Giant roller coaster after a woman was thrown from her seat and plunged to her death.
Between 1990 and 2010, more than 92,000 children were injured in amusement ride-related incidents, according to a study by the Center for Injury Research and Policy at Nationwide Children's Hospital in Ohio. That's an average of more than 4,000 injuries per year. The study looked at both mobile and fixed rides.
It could have been us
For those who witnessed Sunday's accident at the Oyster Festival, it was heartbreaking.
"Just to see all those poor little kids just in so much pain and everything going on, it was really scary," Marsh said.
But for Ello, it hit even closer to home.
He had tried to go on the ride with his daughter, but they were turned away when she didn't meet the height requirements. Seeing injured children lying on the ground after the accident was devastating, he said.
"If she was tall enough, that would have been her," he said, grabbing his daughter's hands. "My heart is broken. I'm speechless. It ruined the day, you know."
CNN's Rick Martin and Sho Wills contributed to this report.