The Effects of Hydrogen Sulfide

According to the OSHA Fact Sheet, hydrogen sulfide is a colorless, odorless and highly flammable gas. It also exudes a "rotten egg" smell. This smell is typically found in sewers, since the breakdown of organic materials, as well as human and animal wastes, produces it. The bacteria in the breakdown of these wastes and materials cause the smell. Hydrogen sulfide also exists as a liquid compressed gas.

Health Effects

• Hydrogen sulfide can affect the respiratory system.

  The effects can vary depending on the duration and level of exposure. A low exposure can irritate the respiratory system, including the nose, lungs and throat. Exposure to hydrogen sulfide can also irritate the eyes. An exposed person may experience a burning sensation in the throat or lungs, runny eyes, coughing or shortness of breath. If these symptoms are prolonged, they can cause headaches, fatigue, inflammation of the eyes and weight loss. Moderate to high concentrations of hydrogen sulfide can cause excitability, dizziness, nausea, shock, convulsions, coma and death.

Hazardous Properties

• Since it's a heavy gas, it lies in poorly ventilated areas such as sewers, basements and manholes. The only route for hydrogen sulfide to enter the body is through the lungs. It cannot be absorbed through the skin. People are aware of hydrogen sulfide by its "rotten egg" smell, although this can only happen in high concentrations. A person in a low concentration area may not be able to smell hydrogen sulfide. The OSHA Fact Sheet advises to never rely on your sense of smell to indicate the presence of hydrogen sulfide or other hazardous chemicals. Hydrogen sulfide can also be explosive when ignited. It may produce other toxic gases such as sulfur dioxide.

Precautions

• It's best to have the right equipment before entering an area with the presence of hydrogen sulfide.

  You should take certain precautions before entering areas with the presence of hydrogen sulfide. The OSHA Fact Sheet mandates testing the air for hydrogen sulfide using detector tubes or a multi-gas meter. The testing will determine if there's any hydrogen sulfide, and if any fire or explosion precautions are necessary. If the equipment detects hydrogen sulfide, ventilate the area by opening doors and windows to help remove the gas. If that's not possible, enter the area with the appropriate personal protective, communicative and rescue equipment. OSHA's Confined Spaces standard provides further information on how to enter a toxic area.