Hydrogen Sulfide Safety
One of the by-products of oil and gas drilling is a toxic gas known as hydrogen sulfide. Also known by its slang names “swamp gas”, “sour gas”, or “rotten egg gas”, hydrogen sulfide (or H2S) is a potentially deadly substance that anyone working around drilling rigs needs to be aware of. Your employer should provide you with safety training that includes dealing with the dangers of H2S. However, especially if you are new to the oil and gas industry, you need to familiarize yourself with hydrogen sulfide, the hazards that it can present, and how to avoid its dangerous effects.
Hydrogen sulfide has some notable characteristics:
- Heavier than air – Because H2S gas is heavier than air, it tends to collect near the bottom of any space where it has a significant presence. That space can be a tank or other type of container.
- Chemical composition – A hydrogen sulfide molecule consists of two hydrogen atoms bonded to a single sulfur atom. This makes its molecular composition similar to that of water (H2O) which, of course, is two hydrogen atoms bonded to a single oxygen atom. This chemical composition means that H2S is a commonly found gas, so don’t assume you won’t encounter it.
- Flammable / explosive – H2S has a “flashpoint” of 500 degrees, which means it can catch fire and burn at or above 500 degrees Fahrenheit. A lit cigarette, butane lighter, or camping lantern is all it takes to ignite a heavy concentration of H2S gas. In fact, H2S gas is three times more flammable than natural gas.
- It’s invisible – You can’t see hydrogen sulfide gas (like many other types of toxic gases), so your sense of sight will not work to help you determine whether it is present.
- Smells like “rotten eggs” as a result of the sulfur content – H2S produces a strong, somewhat offensive odor in lower concentrations which has led to the substance’s many nicknames. However, this odor tends to decrease when H2S is present in higher concentrations and it also can decrease the sensitivity of your sense of smell. These characteristics mean that you should never rely on your sense of smell to detect whether or not the gas is present in a given environment.
- Highly corrosive – Hydrogen sulfide is very corrosive to metals. It can quickly break down metal pipes, tanks, or other metal materials that it comes into contact with. This corrosive nature of H2S can cause pipes or tanks to develop leaks.
- One of the significant hazards in the oilfield – Not only is it common in oilfields, but hydrogen sulfide can act very quickly on an unsuspecting victim – rapidly causing significant injury or death. In addition, it is important to be aware of the effects of alcohol use around H2S gas. While alcohol is prohibited around any drilling environment, alcohol consumption within a 24-hour period before working on a rig can cause an individual to be more susceptible to low concentrations of H2S gas than they might be otherwise.
Hydrogen sulfide is produced by decaying organic materials. The substance can be recovered during refining processes when it is separated from natural
gas or oil and then converted into sulphuric acid or concentrated sulphur. In some cases, however, H2S gas is “disposed” of by burning. Unfortunately, when H2S is burned, it produces another toxic gas: sulphur dioxide (SO2).
So what are the more common tools used in oilfield work environments to avoid H2S dangers? Here are a few:
- Proper and thorough training – Especially for those who are new to oilfield work environments, H2S (and other types of safety) training is crucial and in some cases required by law. However, just because your employer doesn’t provide you with H2S training (perhaps your job won’t require it) doesn’t mean you shouldn’t be familiar with H2S hazards. You should at least be mindful of H2S conditions (via warning signs or flags) within a facility, how to use H2S detection devices, and where the facility’s escape routes are in the event of an emergency.
- Personal protective equipment (PPE) – All oilfield jobs require at least minimal PPE gear such as hard hats, work gloves, safety-toed boots, and high-visibility vests. If you will be working around H2S extensively, you may also be required to carry a gas mask or other safety equipment to be used in the event of an emergency.
- Breathing apparatus – Many oilfield related jobs won’t require you to wear breathing masks and oxygen canisters when working in environments where H2S is present, since you likely won’t be working in enclosed spaces. But some rig jobs require breathing equipment, which means that extensive safety training pertaining to that equipment will be necessary. Those with facial hair probably will require a good shave (if required) as breathing masks or gas masks require an airtight seal in order to work properly, something that is prevented by a beard or mustache. Also, your eyes can be affected by toxic gas along with your breathing: bear in mind that those who normally wear contact lenses should wear only eyeglasses in toxic gas environments.
- H2S detection devices – Some facilities will have H2S warning detectors installed on-site. These detectors will activate alarms when H2S gas reaches critical levels. In addition, depending on your job, you may be required to carry a handheld H2S detector with you at all times when you’re on-site.
- Signage / Warnings – Pay attention to the warning signs and “condition signs” around your oilfield workspace. Condition signs will show that facility conditions are green (normal operations occurring), yellow (caution, high H2S is present), or red (extreme danger – do not enter) conditions. The facilities that you work within should also have wind direction flags to indicate the direction of the prevailing winds, which will affect the travel of H2S gas. To avoid concentrations of H2S gas during an emergency, workers should move upwind and uphill from where the gas is heading (remember that H2S is heavier than air, so it will collect in low-lying areas).
- Your own awareness – Safety and common sense should always be second nature to anyone working in oilfield environments, which can pose many hazards to those who don’t take safety seriously. Pay attention during your safety training. If you aren’t sure about the procedures you should follow when working around H2S gas (or any potentially hazardous materials), then find someone who is experienced and takes the job seriously. Don’t be afraid to ask for help and don’t let your pride put you in a dangerous situation.
You can make good money in the oilfields, but remember to be safety conscious around drilling environments at all times. H2S is one of the most common hazards that you will encounter. Take this toxic substance – and all safety related matters – seriously. A flippant attitude toward safety can ruin your life and the lives of others.
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