 The presence of elevated concentrations of dihydrogen (H2) in the landfill gas is also consistent with elevated temperatures at remote locations some distance from the gas-extraction well.The presence of H2 is consistent with thermal inactivation of -reducing microbes, which normally combine all H2 produced by fermentation of organic acids with to form methane (CH4).H2-producing microbes are less temperature-sensitive than -reducing microbes so that elevated temperatures can inactivate them and their recovery can be delayed over the H2-producers.