Raw biogas itself is generally non-toxic when handled in open, well-ventilated areas, but it can become hazardous to human health under specific conditions. Accidental gas leaks in confined spaces present severe risks of asphyxiation due to high concentrations of carbon dioxide and methane displacing oxygen. Furthermore, raw biogas contains toxic trace amounts of hydrogen sulfide gas, which can irritate respiratory tracts or prove lethal at high concentrations in unventilated chambers.