A warning has been issued by emergency services as lava from a volcano on Spain's La Palma island nears the sea.
Canary Islands officials yesterday said the 1,250C lava may touch the Atlantic Ocean, potentially causing explosions and sending clouds of toxic gases in the air.
Scientists said the clash between the lava and the sea will produce plumes of water vapour loaded with hydrochloric acid.
About 300 local residents in the coastal areas of San Borondon, Marina Alta and Baja and La Condesa have been confined to their homes as the moment of contact between the lava and the sea is likely to trigger explosions and emit clouds of chlorine gas.
As eruptions continue, people have been urged to stay at home, keeping their doors and windows closed while the situation is monitored.
Emergency services on the island tweeted: "Given the possibility the lava will reach the sea in the coming hours on the coastal area of Tazacorte, and in anticipation of possible emissions of gas harmful to health, the Canary Islands volcano emergency committee orders the lockdown of San Borondon, Marina Alta, Marina Baja and La Condesa.
"The population should follow instructions of the authorities and remain at home, with doors and windows closed, until the situation can be evaluated in the morning."
Today, Spain's government classified La Palma as a disaster zone.
The move will trigger emergency subsidies and other support measures.
The government announced a first package of 10.5 million euros (£8.6 million), which includes around 5 million euros (£4.3 million) to buy houses, with the rest to acquire furniture and essential household goods, government spokesperson Isabel Rodriguez said.
Lava has been slowly flowing down the volcano's western flank toward the sea since September 19.
It destroyed almost 600 houses as well as churches and banana plantations in La Palma, which neighbours Tenerife in the Canary Islands archipelago off North Africa.
Local airline Binter, which had planned to resume flights to and from the islands on Monday afternoon, said conditions were still unsafe and that all transfers would be cancelled until Tuesday.
No fatalities or serious injuries have been reported, but about 15% of the island's banana crop could be at risk, jeopardising thousands of jobs.
