What is H2S?

H2S is also known as Hydrogen sulfide, H2S gas occurs when waste builds up in the sewage lines and creates that distinct rotten-egg smell. Hydrogen sulfide is the natural product of the breakdown of organic matter and human waste. Beyond being unpleasant, H2S is corrosive and damages our sewer systems and can cause serious harm or death to people who encounter it.

Because H2S comes from human waste its distribution changes every time our population density does, which is why it can become a big problem in places like campsites, vacation areas, stadiums and other spots that are used seasonally or when city plans change, such as adding new housing developments or building a new city park.

Is H2S dangerous?

Yes! The smell from H2S is irritating, but it’s also a warning as the gas can be incredibly dangerous and destructive if left unchecked. H2S stands for Hydrogen Sulfide, it is produced by bacterial breakdown of organic materials and human and animal wastes and can also be a byproduct of natural gas, hot springs, and crude oil.

The rotten egg smell that pesters neighborhoods is an indication of very low levels of H2S, between 0.1 and 5ppm (that’s parts per million). From 3-5ppm the odor gets stronger and can cause nausea, headaches, tearing of the eyes, and airway constriction. At 20ppm we can add dizziness, irritability, loss of memory, and loss of appetite to the list of symptoms. From 50-100ppm exposure for an hour can lead to conjunctivitis and respiratory tract irritation. Over 100ppm you’ll lose your sense of smell and after 15-30 minutes your breathing will alter and drowsiness will set in, over 48 hours of exposure at this level can lead to death. From 200-300ppm exposure over an hour can cause pulmonary edema (excess fluid in the lungs that makes it hard to breath). Levels from 500-700ppm leads to collapse in 5 minutes, serious damage to the eyes, and death after 30 minutes. 700-1000ppm will knock you out instantly and kill you in minutes and levels over 1000ppm cause instant death.

What do I do if I think I have an H2S problem?

That’s not your job! If you smell gas indoors or outdoors you should immediately evacuate the area and call 911 from somewhere safe to report it. Do not use your cellphone, lighter, or start a car engine in the vicinity of the smell. Once your local fire department checks it out they’ll let you know whether it’s a gas leak or sewer odors from H2S.   

How can I tell the difference between H2S and a gas leak?

If you smell H2S in your neighborhood you’ll want to contact your local wastewater plant, though it can be difficult to get in touch with the right person. If you want help we’re more than happy to provide it, just fill out the form on our contact page with a description of your problem and where the smell is occurring and we’ll get you in touch with the people that can help solve the problem.