All but one of the injured were children.
According to the Norwalk Police Department, a "swing" ride in the Kids Cove apparently lost power, causing the children on the ride to forcefully fall on the ground.
Those with minor injuries were treated and released from the scene.
Several children were more seriously injured, and were transported to Norwalk, Stamford and Bridgeport Hospitals with their parents.
The Oyster Fest remained open during the time of the incident. Other rides were halted while state inspectors checked them out.
Troopers with state police fire and explosion unit are investigating the cause of the failure.