Paignton, Preston and Broadsands beaches in Torbay, Devon, had to be closed and roads to the beaches were sealed off. Coastguard officials, police and even deckchair attendants were drafted in to tend the injured, with 30 people taken to Torbay Hospital. Torbay council said the incident was "classed as a total emergency operation". A fleet of 14 ambulances, including an air ambulance, were called into action.
All the injured suffered cuts to their feet after standing on the shells of dead razor fish, which were buried in the sand. Because of the hot weather there were extreme tides which had caused the sea to go out much further than usual. It meant that people were paddling in areas that were not usually accessible, the Brixham Coastguard said.
Brian Pearce, beach manager for Torbay council, said the scenes had been chaotic with hundreds of bathers streaming out of the sea with lacerations to their feet. "The majority had small cuts, but a few had bad ones which were treated in hospital. I have never seen anything like it. I hope I do not see it again," he said.
Lawrence Parker, reception manager at the Inn on the Green on Paignton seafront, said: "It was chaos. The beach was packed one minute and abandoned the next."
"Some people must have been quite seriously injured because an air ambulance landed on the beach at one stage."
One victim was Ryan Ashington, 15, who had to go to hospital to have stitches in his left foot. His mother, Debbie, said: "The tide was out and just beginning to turn when he ran into the shallows and hurt his foot - he thought he had stood on a stone, but he had cut his left foot. It was about an inch long and very deep and it was pouring with blood," she said.
"I had never seen anything like it in 20 years. People were picking their kids out of the water, and some of the little ones were crying."
Tide levels are expected to return to normal in about three days' time.