British police have issued a warning after a chemical "haze" left up to 50 people on Britain's south coast suffering irritation to their eyes and throats.
Sussex police urged people to keep doors and windows shut in the affected area, between the resort town of Eastbourne and Birling Gap, a few miles along the coast.
Police also warned people to stay away from the beaches, on a busy public holiday weekend.
The haze seems to have been coming in from the sea but the source has not been established, the statement 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 had been enjoying the Bank Holiday weekend sunshine at the beach at Birling Gap with his family, tweeted: "Some sort of chemical incident at Birling Gap, eyes are streaming and there's a strong smell of chlorine in the air".
He had finished swimming when his eyes started stinging. He looked around and saw everyone on the beach also rubbing their eyes and coughing in what he described as "all sorts of strange behaviour".
He told BBC News: "Then looking out towards the water, there was just this crazy foggy haze rolling in off the sea out of nowhere. It was definitely out of the ordinary considering it was a nice clear sunny day 10 minutes beforehand.
"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 just before 5pm.
It triggered call outs to the UK Coastguard, Sussex Police, the South Eastern Ambulance Service and the East Sussex Fire and Rescue Service who said they were treating it as a "chemical incident".
