Hundreds of people have been treated in hospital after a suspected chemical leak along the East Sussex coast.
Birling Gap beach was evacuated on Sunday after people reported breathing difficulties, stinging eyes and vomiting when a “mist” appeared.
Eastbourne District General Hospital says it has treated 233 people.
Investigations are under way into the cause of the “chemical haze”, which was currently unknown, Sussex Police said.
A spokesman said the first report came in just before 17:00 BST where “up to 50 people had been affected by irritation to eyes and throats”.
Six people initially went to hospital with minor symptoms, but as of Sunday night 223 patients were being “decontaminated” at hospital, East Sussex Healthcare NHS Trust said.
Coastguard rescue teams from Birling Gap, Eastbourne, Bexhill and Newhaven raced to help clear the busy beaches as visitors feared they had been struck by a chlorine leak.
Kyle Crickmore, who was at the Birling Gap beach with his family, said it emptied in 10 minutes after people began to feel unwell.
He described how a “foggy haze rolled in out of nowhere” and there was a “strong smell of chlorine in the air”.
“It was definitely out of the ordinary considering it was a nice clear sunny day 10 minutes beforehand,” he said.
“It was stupidly busy and it was a boiling hot day.
“It emptied in about 10 minutes, which was quite staggering considering the amount of people who were there.”
Members of the public alerted emergency services, which triggered call-outs to the UK Coastguard, Sussex Police, South Eastern Ambulance Service and East Sussex Fire and Rescue Service, who said they were treating it as a “chemical incident”.