The yellow nonmetal that is often found near active volcanoes and is used to make sulfuric acid is sulfur. It is typically found in volcanic areas as a result of the release of sulfur dioxide gas during volcanic eruptions. This gas reacts with oxygen and water in the atmosphere to form sulfuric acid, which contributes to acid rain. Sulfur is also widely used in various industrial processes and is commonly extracted from underground deposits known as sulfur mines.