Volcanologist at the Spanish National Research Council (CSIC) Arnau Folch Duran highlights the need to monitor the toxic gas released after a vast stream of white-hot lava reached the sea, sparking fears the contact would release clouds of acidic gas into the air and cause harm to local populations. The Cumbre Vieja volcano straddles a southern ridge in La Palma island, home to 85,000 people, and erupted on September 19, forcing some 6,000 people to flee and destroying hundreds of properties. IMAGES AND SOUNDBITES