A hidden toxin lurks beneath our feet. It fills our sewers and belches from oil refineries. It is highly corrosive and flammable. As a gas, it is colorless and smells like rotten eggs in trace amounts. At high concentrations, it’s nearly unnoticeable until the worst symptoms take effect. Its name is hydrogen sulfide, and it is poisoning workers across the country.
What is Hydrogen Sulfide?
Hydrogen sulfide (H2S) is a naturally occurring gas usually released from decaying organics. It’s what gives sulfur its characteristic rotten egg smell. It comes from microbes found in rotting food, sewage, and animal waste. It also lurks in natural gas deposits, crude oil, and hot springs.
Some manufacturing processes create hydrogen sulfide as a by-product. Paper mills release hydrogen sulfide when digesting wood chips into pulp. Likewise, it is produced in petroleum manufacturing when removing sulfur from crude oil.
Because hydrogen sulfide is toxic to almost all life, it needs to be transported and broken down when created from manufacturing. Industrial facilities collect the hydrogen sulfide gas and process it into elemental sulfur (a fertilizer) and sulfuric acid.
Who is at Risk of Hydrogen Sulfide Exposure?
Hydrogen sulfide is everywhere. If you’ve ever smelled rotting eggs or sulfur, you’ve inhaled at least trace amounts of hydrogen sulfide. For example, natural gas is normally undetectable, but we odorize it with sulfur compounds, including small amounts of hydrogen sulfide.
At very small concentrations, less than 1 part per million, hydrogen sulfide is harmless. There’s usually trace amounts in the air. The risks lie in factories and industrial plants where it appears as a by-product. Sewers are especially susceptible to a high concentration of hydrogen sulfide as the tunnels are enclosed and are designed to have little ventilation.
Sanitation workers must be especially careful and take safety precautions when navigating sewer vaults and pipes. Likewise, wastewater treatment centers hold an enormous amount of hydrogen sulfide, which must be properly collected and converted.
Meat processing plants, especially those dealing in poultry, may produce dangerous concentrations of hydrogen sulfide when heating or roasting the meat. While paper mills and oil refineries are known to produce hydrogen sulfide, they typically collect it for reprocessing. Although hydrogen sulfide exposure is rare for most workers, a leaky pipe or a loose clamp could spell disaster. At sufficiently high concentrations, like those found in industrial facilities, hydrogen sulfide kills within one second.
Swamps and wetlands are also full of hydrogen sulfide. Swamp gas is a mixture of hydrogen sulfide, methane, and carbon dioxide. In rare cases, the swamp gas can become so concentrated that it forms a pit. Then it only takes one unlucky footstep to release a lethal amount of hydrogen sulfide and methane.
What Are the Symptoms of Hydrogen Sulfide Exposure?
Hydrogen sulfide exposure can be frightening. While the gas has a rotten egg smell at less than 1 part per million (ppm), it quickly paralyzes your sense of smell. You may think the smell has dissipated, but you don’t realize that you can’t smell at all. If you’re ever unsure about how the amount of hydrogen sulfide is in the air, you can use an H2S detector.
As the hydrogen sulfide concentration rises to 50 ppm, its corrosive properties burn your eyes and eat away at your windpipe. It’s important to wear a sealed respirator, eye protection, and other safety equipment when working around areas exposed to hydrogen sulfide.
At higher concentrations, 100-250 ppm, the toxicity takes hold. The eyes sting, and the throat burns, potentially causing lasting damage. The throat burns. 100% of people exposed to this level of hydrogen sulfide experience a pounding headache and about half experience nausea.
Between 300-550 ppm, hydrogen sulfide numbs the nervous system. Vomiting ensues, fluid fills the lungs; it can be difficult to keep balance and stand up. At concentrations over 500 ppm, victims completely lose balance and stumble until they collapse and are unable to move.
Finally, at 800 or more parts per million, hydrogen sulfide paralyzes the lungs. Death occurs in minutes or seconds. Only immediate extraction and forced oxygen can prevent the unthinkable.
It doesn’t always take a high concentration to feel the effects of hydrogen sulfide exposure.
Those repeatedly exposed to low concentrations (2-19 ppm) of H2S can develop symptoms associated with the 100-250 ppm range after several days.
Treating Hydrogen Sulfide Exposure
If you ever experience the basic symptoms of hydrogen sulfide exposure, you should leave the area immediately and alert a HAZMAT specialist. Toxic gas is often imperceptible without scientific instruments. You cannot work through it or even fix the issue without proper safety equipment.
There are two treatment options for hydrogen sulfide exposure, and both require a medical professional or specialized medicines. Victims are advised to inhale alkyl nitrates (not to be confused with smelling salts) until they receive further support or an antidote. Experts also recommend Cyanide antidote kits (which contain an intravenous nitrate injection).
It may sound grim, but at toxic concentrations, those who have fallen to hydrogen sulfide cannot be rescued without proper safety equipment. In 2017, three Florida utility workers died within three seconds of climbing down a manhole saturated with hydrogen sulfide gas. A firefighter tried to recover the men but collapsed the moment he removed his air tank. The message is clear. If you witness hydrogen sulfide exposure that causes others to collapse, the best thing you can do is leave the area as quickly as possible and call for emergency services and HAZMAT specialists.
If someone you love has passed away from hydrogen sulfide exposure or if you were poisoned by hydrogen sulfide gas due to negligence or OSHA violations, you may be entitled to financial compensation. If you’d like an experienced North Dakota attorney from Pringle & Herigstad to review your case, please send us an email or give us a call at (701) 599-4337.
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