Why Is Hydrogen Sulfide (H2S) Dangerous?

It may form when organic material breaks down without oxygen. It can collect in sewers, wet wells, sludge areas, tanks, and enclosed process spaces. It is often called H2S.

Low amounts may smell like rotten eggs, but smell is not a safe warning. The gas can reduce a person’s ability to smell it. Higher exposure can cause collapse and death.

Use fixed or portable monitoring as required. Ventilate and control the source when possible. Leave immediately when an alarm or symptom occurs. Never attempt an unprotected rescue in a suspected H2S atmosphere.

Wind and building pressure can move gas toward unexpected areas. A worker outside a hatch may still be exposed if the opening vents toward the breathing zone. Approach from the safer side when the procedure directs it and use remote sampling before opening further.

Hydrogen sulfide can corrode concrete, metals, electrical parts, and instruments. Corrosion damage may create structural or equipment hazards even when gas readings are acceptable at that moment. Report damaged covers, ladders, railings, fasteners, and wiring in areas with a history of gas.