Swamp gas, also known as marsh gas, is a natural gas that forms in wetlands and swamps. It primarily consists of methane, which is produced by the decomposition of organic matter in anaerobic (low-oxygen) conditions. This process is carried out by microorganisms that break down dead plants and animals, releasing methane as a byproduct. Swamp gas can sometimes be seen bubbling up through the water in swamps or marshes. It is flammable and can ignite if it comes into contact with a spark or flame. While it is a natural phenomenon, large accumulations of swamp gas can pose safety risks in certain situations.