The Hazards of H2S Gas

What is H2S Gas?

H2S gas is a chemical compound that stands for hydrogen sulfide carbonyl sulfide gas. It is a colorless gas and is commonly recognized by its distinct rotten egg smell. H2S gas is also widely referred to as sewer gas, sour gas, stink damp, or hydrosulphuric acid. H2S is extremely poisonous to humans, corrosive, and very flammable. When it burns, H2S emits another deadly gas: sulfur dioxide, which has similar symptoms and outcomes to H2S exposure. Unfortunately, year after year workers is incidentally exposed to H2S, many of who suffer detrimental consequences since an unsafe amount can kill a worker in under 10 seconds.

Where Can It Be Found? 

H2S is soluble in water and oil. It could be released anytime the substance is heated or depressurized. It is found in crude petroleum, natural gas, some mineral rock, and hot springs. Therefore, the drilling and extraction of crude oil and natural gas create hydrogen sulfide emissions. It may also be present when bacteria in organic materials or human/animal waste arse broken down in the absence of oxygen. Industries that produce the most substantial amounts of H2S gas include wastewater treatment, tanneries, paper mills, glue and dye production, the mining industry, construction, and the drilling and refining of natural gas.

The gas itself is heavier than air and therefore tends to build up in confined, low spaces. Areas with poor ventilation, such as sewer lines, manure pits, or basements, are likely places for H2S gas to collect and sit. Other settings where H2S may be a concern include the breaking down of wood into pulp, working in swamps or landfills, and in mining situations where mineral rock is present.

Symptoms and Warning Signals 

H2S can be deadly even in the smallest quantities, and significant levels of the gas often kill the victim’s sense of smell. Therefore the distinct “egg odor” should not be used as a measure of how much H2S is present. A worker can find themselves in a fatal situation in mere seconds. If there are low levels of H2S present, eye soreness, breathing troubles, coughing, runny nose, headache, confusion, nausea, or disorientation may occur. H2S is so deadly due to the small amount that is capable of killing a worker. Thus, any symptoms that may result from even the lowest level of H2S should not be taken lightly.

Hazards and Risks Associated with H2S Gas Exposure 

H2S is considered as an irritant and a chemical asphyxiant, which is any substance that inhibits the flow of oxygen from our bloodstream to our cells or prevents cellular respiration even if there is ample oxygen in the immediate environment. In other words, H2S can effectively stop a worker’s ability to breathe when the lungs absorb the gas. Depending on the level present, a worker will generally notice irritated eyes, running nose, and coughing. If the levels increase, the consequences are increasingly severe, with side effects mentioned previously beginning to occur, like dizziness and nausea to death within seconds.  

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Who is at Risk? 

Workers who are most likely to be exposed to unsafe levels of H2S gas include those employees who are required to work in small or confined spaces with poor ventilation. A construction worker entering a drainage ditch, for example, could encounter H2S immediately and be unable to react in time. Employees working with any ignition sources are also at risk because of the flammable nature of H2S. Furthermore, the gas is extremely explosive and can be triggered near cigarettes, pipes, or even matches. An environment that has “still air” is also risky. Anywhere that does not permit the free flow of fresh air can result in a gas collection that can very quickly build to a toxic level. Lastly, employees who are not educated on the warning signs of the presence of H2S gas are most at risk. This could include any workers across all industries. Protocols should first and foremost educate workers on the importance of a respiratory device when inspecting an H2S leak or rescuing a co-worker. Being aware of the warning signals, symptoms, side effects, and protocols could save your life and the lives of your co-workers.

Other resources to workplace hazards

Hazards exist in every workplace, but how do you know which ones have the most potential to harm workers? By identifying hazards at your workplace, you will be better prepared to control or eliminate them and prevent accidents, injuries, property damage, and downtime. You can read more about the 6 types of workplace hazards on our previous blog article

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