Hydrogen sulfide gas, or H2S, is an unsafe and potentially deadly industrial hazard. As such, it’s important to understand what it is, how it can impact your daily duties, the safety precautions you should take in the event of exposure, and how to best protect yourself and your co-workers.
H2S is colorless and cannot be seen with the naked eye, though it can sometimes be detected by its rotten egg odor. However, it is important to note that smell is not a reliable indicator of its presence nor absence (more on this later).
Hydrogen sulfide gas is also very dangerous—it has toxicity comparable to carbon monoxide and is flammable, poisonous, and corrosive. At its worst, it can incapacitate a human in several breaths and can kill nearly instantaneously, depending on exposure levels.
Below we’ll give you a quick primer on H2S gas in the work environment. We also highlight some clothing options from MCR Safety that can help keep your gas detection equipment close at hand and help you maintain a safe “breathing zone” on the job. And, we take a look at gloves, goggles and other PPE workers need when working around H2S.
What Is H2S Gas?
H2S is the abbreviation for hydrogen sulfide, or what is otherwise colloquially referred to as “sewer gas,” “stink damp,” “swamp gas,” and “manure gas.” It is the byproduct of microbes that consume organic material in an oxygen-free environment and results as a product in several specific industrial processes.
H2S OSHA Facts
Below are some facts about H2S and its dangers, as noted by OSHA:
- H2S weighs more than air, and it moves low across the ground. It collects in poorly ventilated areas like basements, maintenance holes, sewers, underground telephone vaults, and manure pits.
- H2S is most dangerous when inhaled; absorption through the skin isn’t very dangerous unless the gas is concentrated in liquid form.
- H2S is extremely flammable, and gas/air mixtures can be explosive. The mixture can drift and travel to sources of ignition, then flashback when ignited, producing vapors and gases like sulfur dioxide.
- Liquid H2S can cause “blue skin” or frostbite.
Where Can H2S Be Found?
As we mentioned earlier, H2S forms when microbes decompose organic materials in an environment free of oxygen. Thus, it commonly forms in septic tanks, cesspools, stagnant water, sewers, and swamps. H2S occurs naturally in crude petroleum, natural gas, and hot springs. Significant pockets of it also exist in the atmosphere from the exhaust of automobiles.
Hydrogen sulfide (H2S) is commonly found upstream, during the production of crude oil and natural gas. Large deposits of natural gas and petroleum often contain pockets of gas, which means oil and gas workers are always on guard for H2S. MCR Safety products are used heavily across the oil and gas industry to keep workers safe. We will discuss some of the improvements made to our FR clothing that help oil and gas workers quickly identify H2S.
Besides oil and gas, H2S is used to manufacture other chemicals and is involved in numerous manufacturing processes. Here is a list of common areas where someone is likely to encounter H2S gas:
- Natural gas deposits, mineral rock, some swamps and bogs, and sometimes even hot springs.
- Over time, decomposing human and livestock waste will give off H2S.
- Sewer and wastewater treatment plants, gas plants, and utility facilities.
- Pulp and paper mills, sewers, commercial labs, petrochemical plants, and oil batteries.
- Coke ovens and tanneries.
- Food processing, agricultural silos, and pits.
- Mine sites, coal-bearing rock, and groundwater bodies
- Hot asphalt paving.
Workers are most commonly exposed to hydrogen sulfide by breathing it. What makes that complicated is that H2S gas is a silent threat for workers, which means workers must constantly check for increasing concentrations of the gas. If gas levels are not checked often, H2S hazards can wreak havoc on workers, causing symptoms few workers wish to encounter.
As mentioned in the beginning, some people may be easily alerted to the presence of H2S by the smell of rotten eggs at relatively small concentrations. However, exposure, at even very low levels, can cause olfactory desensitization. At higher levels, a person’s sense of smell can be neutralized almost instantly. Because of this, a sense of smell is never a reliable indicator of the presence or absence of H2S.
What are the symptoms to be looking for in H2S exposure? As in the image above, a headache can often be a strong indicator that something may be wrong. Exposure to H2S can cause a wide range of effects depending on the amount of gas the individual breathed and for how long. Below is a breakdown of what symptoms to expect from different exposure levels.
Symptoms of short-term exposure include:
• Eye irritation
• Skin irritation
• Deadened sense of smell
Repeated or prolonged exposure to moderate levels can cause:
• Low blood pressure
• Loss of appetite
• Weight loss
• Painful rashes
• Irritated eyes
At high concentrations, H2S has a sickeningly sweet odor. Repeated exposure to high levels of H2S can cause:
• Brain damage
• Heart damage
H2S can cause what’s known as “the knockdown effect” - when workers are exposed to so much gas, they undergo a rapid loss of consciousness. This level of exposure can cause long-term symptoms, which include:
• Reduced attention span
• Reduced motor functions
• Delayed pulmonary edema
• A buildup of excess fluid in the lungs
Exposure to H2S at the highest levels can cause rapid unconsciousness and knockdown or immediate collapse in just one or two breaths. Breathing can stop, and death can occur within minutes. At 1,000 to 2,000 ppm, death is nearly instantaneous. So, to say the least, workers must take H2S seriously at all times, especially if they work in an area where it is commonly found.
Hydrogen Sulfide First Aid
Lengthy exposure to hydrogen sulfide may result in painful dermatitis and burning eyes. Direct contact with liquefied gas can cause frostbite. It is important that anyone performing first aid for exposure to H2S knows what they’re doing.
If you’re required to provide first aid to an individual who has been exposed to H2S, there are some helpful resources to review before the knowledge needs to be applied. For workers who have inhaled H2S, two excellent resources to review are OSHA’s first-aid guidelines involving the gas and the Canadian Centre for Occupational Health & Safety’s fact sheet for hydrogen sulfide. Some of these first-aid procedures require advanced first-aid training, which we don’t cover in this blog article.
OSHA H2S Pointers
Here are some of OSHA’s pointers for someone who encounters a worker with either H2S skin contact or eye contact:
SKIN CONTACT - Contact with liquefied H2S gas can freeze the skin.
Below are OSHA’s first-aid guidelines in case a worker’s skin is exposed to H2S:
• As quickly as possible, remove the victim from the source of contamination.
• Don’t rub the area or apply heat directly.
• Get rid of any clothing or jewelry that might restrict circulation. Cut around clothing that sticks to the skin and remove the rest of the garment.
• Cover the affected area with a sterile dressing.
• Don’t allow the victim to drink alcohol or smoke.
• Transfer the victim to a hospital.
• Double bag, seal, and label the contaminated clothing and leave it at the scene for safe disposal.
EYE CONTACT - H2S gas irritates the eyes.
Below are OSHA’s guidelines in case a worker’s eyes are exposed to H2S:
• In the case of contact with H2S gas, immediately wash the victim’s contaminated eye(s) with lukewarm, gently flowing water for about 15 to 20 minutes while holding the eyelids open.
• Do not attempt to rewarm any areas where contact has been made.
• Cover both eyes with a sterile dressing.
• Immediately call a poison center or doctor, and transport the victim to a hospital. Treatment is urgently required.
Additional sources of information:
• Vivid Learning Symptoms: https://vividlearningsystems.com/blog/how-to-protect-against-the-dangers-of-hydrogen-sulfide
• Wikipedia: https://en.wikipedia.org/wiki/Hydrogen_sulfide
• Effects of H2S: https://www.youtube.com/watch?v=KsJ6YCkZGoM
• WorkSafeBC: https://www.worksafebc.com/en/resources/health-safety/books-guides/hydrogen-sulfide-in-industry?lang=en&direct
How Worksites Can Protect Against H2S
At its highest levels, H2S can incapacitate someone or worse. As a result, effective protection and education about the hazard can mean the difference between life and death.
There are a couple important steps workplace management can take to help prevent H2S exposure accidents.
- Safety equipment should be readily available and easy to access at all times. To assist workers in avoiding eye or skin contact with H2S, check out MCR Safety’s online safety glass catalog and online glove catalog.
- Any worksite with H2S concerns should have mandatory educational programs, and all employees should be well-informed about evacuation drills and contingency plans.
Worksite management is responsible for H2S monitoring and assessment, as well as the tracking of medical records and statistics regarding any workers exposed to the gas. They are also responsible for the provision of generalized equipment, like safety glasses and protective clothing, but also more specialized equipment (which we’ll touch on a little further below).
An H2S Monitor and Detector
H2S monitors are an important piece of equipment found on any worksite where H2S is a concern. Industrial H2S monitors have progressed over the years, now with optical sensing technology able to measure the different intensities of IR or UV to determine H2S concentration.
Even with the best technology present for H2S detection, sometimes, what is most important is the placement of that equipment. Because the most common type of H2S exposure is inhalation, having the detector located within the breathing zone is likely to yield the best results and provide optimal safety. OSHA defines the breathing zone as “a hemisphere forward of the shoulders within a radius of approximately six to nine inches.” Wearing the detector on one’s lapel or breast pocket will typically meet this criterion. Keeping the instrument visible and within proximity will help notify a worker of any alerts. Visibility of the detector is key for workers who have any hearing impairment or for those working in a high-noise environment.
As we mentioned above, MCR Safety recognizes H2S as a serious threat to worker safety. While we don’t manufacture the actual detectors themselves, we have engineered our new line-up of FR clothing with Summit Breeze® technology to assist in their use and have developed specially-designed mesh monitor holders to hold gas detection equipment.
FR Clothing Mesh Monitor Holder
We manufacture our PPE with one thing in mind, protecting people. Keeping the detection monitor close at hand and visible to workers helps increase safety. We highlight more benefits of our FR clothing lineup below.
MCR Safety FR Clothing – Triple-Vented
MCR uses patented Summit Breeze® technology in our FR clothing. What’s special about this FR technology? Its mesh venting is incorporated onto the back and under the arms, allowing body heat to escape where it builds up the most.
Summit Breeze® technology provides better heat stress management for those working in a hot environment, those who are performing labor-intensive tasks, or a combination of the two. When working in an environment prone to heat stress, vented openings can be a lifesaver. MCR Safety is the only manufacturer providing FR clothing with three total FR mesh vent openings, allowing for exceptional airflow.
Summit Breeze® Technology
Sometimes it’s tempting to choose the cheapest clothing option and save a buck, but you risk putting yourself in danger when you do not select workwear that is both flame-resistant and designed to keep you cool and comfortable. The least-expensive garment that meets the minimum requirements of the standard may not be the best value in the long run.
MCR Safety’s FR Clothing Resources
MCR Safety believes in offering high-quality products that provide superior protection. In addition to that, we are passionate about making sure you’re informed when making crucial PPE decisions. That is why we offer electrical workers links to numerous resources to stay up-to-date on all relevant PPE, standards, hazards, and much more.
Here are the resources we’ve assembled to help you find the most appropriate FR clothing:
Summit Breeze® PDF on the left side; FR Online Catalog on the right side.
Workers don’t mess around with H2S, and neither does MCR Safety. We recognize the fact that workers need PPE that supports them in the field. Our new collection of FR clothing, including coveralls, comes with built-in mesh monitor holders for gas detection equipment. We may not be able to eliminate H2S in your work area, but we will make sure our PPE offers you an easy, convenient way to keep your monitor within your breathing zone!
For over 45 years, MCR Safety has proven to be a world leader in gloves, glasses, and garments. Whether it’s on the shop floor, an oil rig or a construction site, we are there providing solutions to workplace hazards. It’s all part of our commitment to protect people.
No matter your industry, we have the personal protective equipment you need.
We Protect People!
For more information, browse our website, request a catalog, find a distributor, or give us a call at 800-955-6887.