Raw, unburnt biogas is generally non-toxic, but it poses significant health and safety hazards if leaks occur in poorly ventilated indoor spaces, primarily due to the presence of toxic trace gases like hydrogen sulfide and asphyxiating levels of carbon dioxide and methane that can displace oxygen. Furthermore, burning any biomass fuel indoors without adequate chimney ventilation releases particulate matter and combustion byproducts that can irritate respiratory pathways, making proper system installation, outdoor placement, and routine maintenance essential for domestic safety.