The contact of the lava from the La Palma volcano with the sea water, where it arrived on Tuesday night, produces clouds of acid gases that can cause corrosion and have effects on the respiratory system, in addition to causing irritation to the eyes and the skin. skin. But the consequences of contact with these gases, similar to etching (household cleaner composed mainly of hydrochloric acid), require prolonged and unprotected exposure to be serious. In addition, the atmosphere allows for rapid dissolution of concentrations. According to the Cabildo de La Palma, the air in the area far from the outlet of the wash is “perfectly breathable” and “no values have been recorded that are considered harmful to health”.
Antonio Romero, professor of Chemistry at the University of Seville, explains that, basically, the lava reaches the coast at about 1,000 degrees and comes into contact with sea water, which is at a temperature of 23 degrees. This thermal shock generates a cloud of gases. “If it were pure water,” he adds, “nothing would happen, but the sea water has dissolved ions that are chlorides and sulphates that are incorporated into the steam generated and, in the atmosphere, they react with water molecules to form hydrochloric and sulfuric acids. and hydrofluoric. But, as chlorine is the most abundant, mainly hydrochloric; something similar to what people know as etching is produced ”.
Photogallery: The arrival of the lava from the Cumbre Vieja volcano to the sea
Romero explains that these acids are corrosive and aggressive, but in concentrations that are not those that are given by the contact of the lava with the sea. “If there is a continuous and unprotected inhalation, these gases pass into the pulmonary alveoli and the mucous membranes. In the case of the skin, you can notice irritation, but you have to be breathing that water vapor, for a long time and without a mask ”. The Instituto Vulcanológico de Canarias (Involcan) confirms that “inhalation or contact with acid gases and liquids can irritate the skin, eyes and respiratory system and cause breathing difficulties”.
Juan Acosta Rodríguez, a resident of Las Indias, was the only official fatality in the previous volcanic eruption in La Palma, that of Teneguía or Cumbre Vieja, on October 26, 1971. He lost his life after violating the security cordon, by inhalation of toxic gases in the Los Percheles area. And it is suspected that this same cause was related to the death of the photographer Heriberto Felipe Hernández, from Santa Cruz de La Palma, who died in the hospital with symptoms of intoxication after having previously ventured on several excursions to the area.
CSIC volcanologist Joan Martí specifies that the amount of gases released by lava when it comes into contact with seawater on La Palma is small and will disperse “very quickly”, so the condition is “very local” and it does not generate problems if the recommendations of the authorities are followed
The chemist from the University of Seville agrees: “The atmosphere has a great capacity to dilute all that concentration and, as the gases move away from the source of emissions, where the lava is falling, a dilution will take place.” “Keeping the distance perimeter established by the authorities, in principle, there should be no problem.”
In the case of the La Palma eruption, the acid concentration exceeds normal values due to the emissions of carbon dioxide, hydrochloric acid and sulfur derivatives that are produced from the sulfuric acid provided by the lava. However, Rubén Fernández, from the Canary Islands Volcanic Emergency Plan (Pevolca), believes that the situation is favorable due to the effect of the wind, which dissipates the column and spreads it towards the sea. “We do not have any indication that makes us think that it is dangerous for the people who are in confinement or for the emergency teams, who also respect the security perimeters”, remarks Fernández.