H2S is one of the leading safety related concerns in the petroleum industry in Alberta. In addition, it is prevalent in pulp and paper mills, barges, sewer systems, land fills, waste water treatment facilities and pig farms. As a result of its toxic and flammable characteristics, emphasis has been placed on safety procedures when working around this naturally occurring gas. Its main route of entry is by inhalation which can lead to pulmonary edema, conjunctivitis of the eyes, respiratory problems, and if in enough concentration to a worker’s death.
Hydrogen sulfide gas is colourless in nature and has a repulsive rotten-egg smell at smaller concentrations. People become exposed to it when they inhale it, which can cause respiratory and cardiac failure. Due to its corrosive properties, is also damaging to mucous membranes. It can form sulfuric acid on contact with sinus cavities and eyes . causing severe burns to human tissue . H2S is a secondary byproduct of many industrial processes but it is also generated when an organic matter decomposes. Because it is a little denser than air it is particularly dangerous in confined spaces or low-lying areas. Examples of potential areas where it might accumulate are under the sub structure of a drilling rig or in the mud tanks. In plants, it can depressurize from valves, seals, unions, thief hatches, sample valves, pipes or in high pressure buildings such as compressors, dehydrators, separators or treater units. In temperatures of 260oC (500F) or even lower, hydrogen sulfide can exhibit explosive reactions. Its flammable range is approximately 42%, with a lower explosive limit of only 4.3% when mixed with air. Static electricity and flammable vapours can result in ignition, so it is important to use intrinsically safe equipment when working near potential areas for the gas.
It is commonly called sewer gas , stink damp or sour gas or by its other spelling “hydrogen sulphide”. Burning it can produce an even more explosive, toxic and corrosive gas, sulphur dioxide, which can be seen above flare stacks. Both gases are serious environmental concerns and are closely monitored by environmental agencies.
It is a Deadly Poisonous
Hydrogen sulfide is extremely poisonous to carbon based life forms. When you breathe it in through your lungs, it enters into your bloodstream. In order for your body to protect itself, it strives to break the gas down very quickly into a non-harmful compound. Poisoning of the blood begins when the rate at which the gas is absorbed becomes higher than the rate at which it is removed from the blood. It is a nerve gas, classified as a chemical axphiant, causing respiratory failure in low does.