On Sunday, a mysterious chemical mist swept onto Beachy Head, East Sussex, sending 150 people to the hospital with sore throats, burning eyes, nausea and breathing trouble.
The medical complaints were "mostly minor," authorities said. Local police cautioned residents to keep doors and windows closed and to stay away from the beachfront areas that were most affected. The mist came onto shore with particularly poor timing: the past weekend was England's Bank Holiday, a busy time for vacationers, and many tourists and locals were out enjoying the fine weather.
Newhaven and Eastbourne RNLI Lifeboat volunteers launched on Sunday evening to help authorities search for the source of the mist. They spoke with boaters in the area and checked the beaches to see if there were any injured bystanders, but they found no additional casualties. RNLI Eastbourne member Bob Jefferey told The Express that the mist smelled like "burnt plastic," and added that it had largely dissipated by Monday.
The mist's source and composition are unknown. Online speculation as to the cause of the incident varies: popular proposals included an industrial accident in France, terrorism, a discharge from a water treatment plant, Russian interference or Brexit (all unlikely). Some beachgoers suggested that the mist was chlorine gas, but the local police said that this too was “extremely unlikely.” Alternatively, Dr. Simon Boxall of the UK's National Oceanography Centre told media that the conditions in the English Channel were ideal for an algae bloom on the day of the incident, and that algae-related events with similar symptoms have been reported elsewhere.
"Neither the gas nor its source have been established, but agencies are continuing to investigate and have not ruled out either on-shore or off-shore locations, although it does appear that it did sweep in from the sea driven by on-shore breezes," said Sussex Police in a statement.