Hydrogen sulfide (H2S) is a colorless gas that is toxic to humans and animals. H2S gas is produced during the decomposition of organic material and is commonly found in sewers. H2S gas is measured in parts per million (ppm) and the National Institute for Occupational Health and Safety (NIOSH) has set a ceiling limit of 10 minutes at 10ppm for exposure for workers. NIOSH has also determined that 100ppm of H2S poses an immediate risk to life. While the presence of H2S in homes is uncommon, malfunctioning or improperly installed sewer pipes can allow H2S to enter into homes from the sewer. 

The effects of H2S are similar to carbon monoxide. H2S can cause headaches and nausea at low concentrations, and memory loss, brain damage, or death at higher concentrations. Unlike carbon monoxide, which is not possible to smell, hydrogen sulfide has a strong stench of sulfur, which is commonly associated with the smell of rotten eggs. If a house is having sewer line issues which is causing H2S to enter the home, it is not only unpleasant, but it poses a risk to health and life since it is toxic. Consumer H2S meters and detectors are not common, but since H2S has such an unpleasant smell, it is not a "silent killer" like carbon monoxide. If you smell sulfur or a rotten egg smell in your house, it is important to open windows to improve ventilation, and potentially leave the house if you are having any side effects of H2S exposure. 

Due to the dangerous nature of hydrogen sulfide and the ease with which it can be tested, Timberline Ridge Home Inspections performs FREE hydrogen sulfide testing on the properties we inspect. The maximum reading will be listed in the inspection report, and we will attempt to determine the source of the H2S in the property. For more information regarding hydrogen sulfide and the dangers it poses, talk to your doctor or visit www.CDC.gov/niosh/topics/hydrogensulfide/