What are the dangers of Hydrogen Sulfide (H2S)?

By Tess de Hertogh on Jun 07 in Blog.

What is Hydrogen sulfide?

One of the gases that is commonly found in various industries and on ships is hydrogen sulfide, also known as H2S. Known by its foul smell of rotten eggs, hydrogen sulfide is a product of organic material which decays in the absence of oxygen. Hydrogen sulfide is a gas that is poisonous, corrosive and highly flammable. Hydrogen sulfide is a dangerous gas for our bodies and can be lethal in high levels of exposure.

The dangers of hydrogen sulfide

Hydrogen sulfide is dangerous for the body because it inhibits the respiration of cellular respiration which damages the central nervous system. At lower concentrations, hydrogen sulfide will be met with a scent of rotten eggs. After prolonged exposure the smell will no longer be distinguishable. Hydrogen sulfide is scentless at higher levels of concentration.

  • < 10 ppm: fairly harmless even though burning sensations can be felt in the eyes and lungs. This is the OSHA permissible exposure limit.
  • 10 – 100 ppm: severe breathing problems, headaches and eye irritation.
  • > 100 ppm: exposure to these levels can be life-threatening: this includes inability to breath, rapid unconsciousness, coma and death.

Where is hydrogen sulfide predominantly found?

Hydrogen sulfide is formed during the rotting of many organic materials. Because hydrogen sulfide is heavier than air it tends to accumulate at the bottom of poorly ventilated spaces such as sewers, sewage wells, pumping stations, ship’s cargo holds, silos, overflow wells, storage tanks, crawl spaces, manure cellars, slurry tanks, tanker trucks and many other situations. Entering such a confined space without gas-free measurement is life-threatening.

How to safely handle hydrogen sulfide

Hydrogen Sulfide is a dangerous gas which needs to be handled with care. Therefore it is necessary that the gas is detected at an early stage when working in hazardous environments. Gas detection with a personal H2S detector, a personal multigas detector (which includes a H2S sensor) or a portable multigas detector for tank measurement (which includes a H2S sensor) is of great importance.

What to do when you have come in contact with hydrogen sulfide

When the gas detector which you are carrying gives an H2S alarm, you must leave the room or area where hydrogen sulfide is detected as soon as possible and you must reach an area with fresh air. It is vital to do this as soon as possible because otherwise you may not be able to get away on your own in time, with life-threatening consequences.

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