This critical safety training program addresses the extreme hazards of hydrogen sulfide (H2S), a highly toxic and potentially lethal gas commonly encountered in petroleum refining, natural gas production, wastewater treatment, pulp and paper mills, and other industrial operations. Hydrogen sulfide is particularly dangerous because it is both an asphyxiant that displaces oxygen and a chemical asphyxiant that interferes with cellular respiration, causing rapid unconsciousness and death at high concentrations. At very low levels (0.01-1.5 ppm), H2S has a characteristic 'rotten egg' odor, but at higher dangerous concentrations it paralyzes the olfactory nerves, eliminating the ability to smell it—a phenomenon called 'olfactory fatigue' that provides a false sense of safety. Petroleum workers, wastewater operators, and industrial personnel will learn to recognize the physical and chemical properties of hydrogen sulfide, including its density (heavier than air, accumulating in low areas), flammability range, and toxicity at various concentrations. At 10-50 ppm, H2S causes eye and respiratory irritation. At 100-500 ppm, exposure causes pulmonary edema, confusion, and loss of reasoning. Above 500 ppm, hydrogen sulfide causes immediate unconsciousness, respiratory paralysis, and death within minutes. The course covers comprehensive protective measures including atmospheric monitoring with calibrated H2S detectors, alarm systems and action levels, engineering controls such as ventilation systems, and mandatory use of appropriate respiratory protection including airline respirators or SCBA for entry into H2S atmospheres. Participants learn proper selection and use of personal protective equipment, buddy system requirements, and emergency rescue procedures that prevent would-be rescuers from becoming victims themselves. Additional training topics include work permit systems for H2S environments, evacuation procedures when alarms activate, emergency response protocols including victim rescue and medical treatment, decontamination procedures, and the critical importance of never entering an H2S atmosphere without proper equipment and authorization. This life-saving training ensures workers understand the deadly nature of hydrogen sulfide and the protective measures necessary to work safely in environments where H2S may be present.