On 27 March 1931 the first fumarole exploded with a force and a roar so constant that local residents sealed doors and windows to be able to sleep. The noise was such as to be heard in the cities of Volterra and Massa Marittima, 25 km away. In 1936, Ferrovie dello Stato opened a new 60 MW power, producing two million pounds of water vapor, in addition to natural gas (93% carbon dioxide, 2.5% hydrogen sulphide, 4.5% of residual fuel).
