(Updates with latest figures on injuries, more details of accident, quotes; byline)
By Richard Weizel
MILFORD, Conn., Sept 8 (Reuters) - Eighteen people, most of them children, were injured at a fair in Connecticut on Sunday when a carnival-style swing ride twirling them through the air in circles broke down, sending riders crashing into each other and tumbling to the ground, police said.
None of the injuries sustained by the 17 youngsters and one adult during the mid-afternoon mishap at the Norwalk Oyster Festival was believed to be serious, and only one individual was hospitalized, Norwalk police said.
The so-called Zumur swing ride, in which patrons sit in open chairs suspended by cables from long metal arms connected to a rotating hub, apparently lost power while the riders were airborne, police said.
With the sudden loss of momentum and centrifugal force, the swinging seats slammed into each other and into the center of the apparatus, spilling some of the children 10 to 15 feet (3 to 4.5 meters) to to the ground, Norwalk Police Chief Tom Kulhawik said.
Some of the fallen riders also were bumped by the drooping seats dragging along the ground before the ride came to a complete halt, and one child was bleeding from a heady injury, Kulhawik said.
According to police accounts, the children's parents were all nearby in the Kid's Cove section of the festival grounds, many watching as the ride malfunctioned. No bystanders were reported to have been hurt.
The three-day festival remained open to the public for the final hours of the event, but all the carnival rides were immediately shut down for an inspection by the state fire marshal's office and state police, authorities said.
Organizers of the annual Oyster Festival, now in its 36th year, say the event draws an estimated 50,000 to 60,000 people each year to the waterfront town of Norwalk at the southwestern tip of Connecticut on Long Island Sound, about 40 miles (64 km)from Manhattan.
Aside from saying that the ride appeared to have lost power, police declined to speculate on the precise cause of the malfunction or whether human error might have been a factor.
The Norwalk Seaport Association, which sponsors the festival, said the organization was "cooperating fully with the investigating authorities."
The ride was operated by Stewart Amusement of Trumbull, Connecticut, which posted a brief message on its web site saying a preliminary inquiry into the accident found that the Zumur ride "suffered a mechanical malfunction."
"We are continuing to cooperate with authorities as they investigate into the root cause of the accident," the company said.
Of the 18 people hurt in the accident, five declined medical treatment at the scene while 13 others -- one adult and 12 children -- were taken to area hospitals. Only one patient was admitted. The rest were treated and released, police said. (Reporting by Richard Weizel; Writing by Steve Gorman; additional reporting by Jonathan Kaminsky; Editing by Steve Gorman and Nick Zieminski)