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 H2S: What’s that smell? 

Most of the hazards on our job site are things we can see. But what about invisible hazards like hydrogen sulfide (H2S)? Commonly known as sour gas, H2S is a deadly gas that forms when organic matter decays. It is prevalent in the oil and gas industry, and it is a byproduct of many industrial processes, including hot asphalt paving. If you learn to recognize H2S and follow safety procedures, you can protect yourself from overexposure: 

  • Stay alert when working in conditions that increase the risk of H2S exposure, such as in manholes and other confined spaces, windless or low-lying areas, marshy landscapes, and hot weather that speeds up the rotting of manure and other organic materials. 

  • Make sure a qualified person uses proper equipment, such as an electronic meter, to test for H2S before you enter the area. 

  • Use your nose. H2S smells like rotten eggs at low concentrations. Don’t rely only on your nose, however, because you can lose your sense of smell the longer you are exposed to H2S. 

  • Don’t smoke; H2S is flammable. 

  • Wear your personal H2S monitor at all times. If it goes off, get upwind immediately. Workers often wear their monitor within 10 inches of their nose and mouth, but consult the manufacturer for proper placement. 

  • Learn how to properly use and maintain your respiratory protection. 


Discussion questions: 

  • Why shouldn’t you count only on your sense of smell to warn you that H2S is in the air? 

  • What should you do if your H2S monitor goes off? 

  • How do you identify where upwind is? 

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