What is H2S? Sources of the Dangerous Gas

An overview of common H2S sources


H2S, or hydrogen sulfide, is a colorless gas that is flammable and extremely hazardous. The gas is often associated with “rotten egg” smell and can be very dangerous to be around. 

Before we get into more details about safe and dangerous concentrations of H2S and how to manage scenarios of concentrations of H2S it is important to understand the sources of this gas. In today's blog, we will take a quick look at the natural and man-made sources of H2S. 

H2S is formed when bacteria breaks down organic material. This can happen in natural sources such as in crude petroleum, natural gas, and hot springs. It can also be naturally found in human or animal waste and sewage. Industrial activities that can also produce H2S include petroleum/natural gas drilling and refining, wastewater treatment, coke ovens, tanneries, and kraft paper mills. Hydrogen sulfide can also exist as a liquid compressed gas.

Here's a closer look at some common sources:

  • Organic Decomposition. H2S is present in swamp and sewer environments, which is why these areas emit the odors that we often smell.
  • Geomorphology and Chemical Reactions. H2S is present in areas of active natural geomorphology such as volcanoes, hot springs and underwater sub-sea vents. 
  • Man-made environments and industries. It is often found in the farming, coal mining, pulp and paper, petroleum, tanning and smelting industries. The largest industrial cause of H2S is through petroleum refineries as the hydrodesulfurization process separates Sulfur from petroleum. Small amounts of H2S occur in crude petroleum and natural gas can contain up to 90% H2S.

The main focus of H2S training is for individuals working in the petroleum industry where safety concerns with this toxic gas are high. We will take a closer look at the dangers of H2S and safety training in our next blog.