Taftan displays vigorous fumarolic activity, with high temperature vents found around the crater. Fumaroles are found chiefly in the eastern and at the edge of the western crater, with minor fumaroles within the western crater, along some minor craters and along the major lava flow. These gas exhalations are known as Dood by local peoples and they appear as yellow-white clouds with a strong smell. The vents they come from have the shape of fissures, cracks and crevices. The larger fumaroles can reach diameters of . The occurrence of hydrothermal explosions has been inferred from the presence of breccia made up by volcanic rocks.