Sewer Gas - Health Effects

Health Effects

In most homes, sewer gas may have a slightly unpleasant odor, but does not often pose a significant health hazard. Residential sewer pipes primarily contain the gases found in air (nitrogen, oxygen, carbon dioxide, etc.). Often, methane is the gas of next highest concentration, but typically remains at nontoxic levels, especially in properly vented systems. However, if sewer gas has a distinct “rotten egg” smell, especially in sewage mains, septic tanks, or other sewage treatment facilities, it may be due to hydrogen sulfide content, which can be detected by human olfactory senses in concentrations as low as parts per billion. Exposure to low levels of this chemical can irritate the eyes, cause a cough or sore throat, shortness of breath, and fluid accumulation in the lungs. Prolonged low-level exposure may cause fatigue, pneumonia, loss of appetite, headaches, irritability, poor memory, and dizziness. High concentrations of hydrogen sulfide (>150 ppm) can produce olfactory fatigue, whereby the scent becomes undetectable. At very high concentrations (>300 ppm), hydrogen sulfide can cause loss of consciousness and death.