Most of the 250 residents of Vulcano, a volcanic Italian island, were ordered to evacuate on Thursday, October 21, after dangerously high carbon dioxide (CO2) levels in the air caused respiratory difficulties in humans and animals. The Italian National Institute for Geophysics and Volcanology (INGV) reports that CO2 levels around Vulcano in the Aeolian archipelago off the north coast of Sicily have risen from 80 tons to 480 tons, drastically decreasing the amount of oxygen in the air. Lipari Mayor Marco Giorgianni issued a guideline establishing a “red zone” where non-researchers and non-civil protection officers are not allowed to stay. Alternatively, people can stay in “yellow zones” but only on the upper floors of their houses. The rule also forbids non-resident visitors and tourists from visiting the island for a month.

“The activity of the volcano gives us reason in this moment to pay attention even if almost all of the data points to a condition of stability,” Giorgianni said on the Lipari Comune’s Facebook page. Four geochemical stations that detect CO2 from the soil are now functioning, according to the INGV’s Palermo and Catania-Etneo Observatory website. The observatory has built seven new seismic stations to supplement the pre-existing ones: six on Vulcano and one on Lipari. A high-definition thermal camera has also been installed to monitor soil temperature.