The Basics to Hydrogen Sulfide Safety

Before the mid-1950’s, very little acknowledgement was given to the risks and dangers lease pumpers face while working with high levels of hydrogen sulfide gases (H2S). Although improvements to drilling rigs have allowed us to achieve depths of over 20,000 feet, experience has shown “the deeper the well, the higher the bottom hole pressure and more H2S gases the lease workers will experience”. In fact, some wells have H2S rates so high, they have to plug the entire well.

While regulations have been written and enacted to protect lease workers from this growing danger, this is still a worldwide concern. Due to these revised laws, regulations, and large court awarded settlements to workers (or their families) when negligence can be shown; most companies typically utilize the best equipment, exposure considerations, literature, etc. they can afford. One of the most important aspects of this is education and training; to help understand more about hydrogen sulfide gas and the dangers associated with it, here are some of the most common questions lease workers have about hydrogen sulfide.

What Is Hydrogen Sulfide?

Hydrogen Sulfide (also referred to as H2S) is a naturally occurring gas produced along with natural gas and crude oil. Like many other gases, it can be fatal if breathed in. Therefore, it is vital for lease workers to have some form of breathing apparatus on hand; as well as understand the warning marks. Tanks containing deadly amounts of hydrogen sulfide are typically marked by a star or some other indicator showing the presence of H2S. When this warning is present, lease pumpers may be required to wear a breathing apparatus when testing or sampling the crude oil.

What Are the Important Properties of Hydrogen Sulfide?

In order to fully understand how hydrogen sulfide acts the way it does, you have to be aware of the physical properties of the gas; with H2S being a colorless gas consisting of two parts hydrogen and one part sulfur. Other properties include:

· Has an API gravity of 47.6

· Has a blue flame when burned

· Has a boiling point -75° F

· Is explosive in the air

· Is slightly heavier than air, thus will seek lower areas

· It attacks a large amount of metals to form sulfides (usually insoluble precipitates)

· It dissolves in water, forming a weak hydro sulfurous acid

· It has a melting point of -119°F.

· It is extremely poisonous

· It is soluble in water

· Liquid density of 0.790 @ 60°F

· Typically gives off an odor of rotten eggs in small doses. However, higher concentrations can cause the olfactory nerve to be paralyzed within 60 seconds, making the odor undetectable.

What Are the Dangers of Breathing H2S?

The toxicity level of H2S is typically determined by the parts per million (or ppm) in the air. This means a 100 ppm concentration of hydrogen sulfide is equivalent to 100 liters of H2S in a million liters of air. How a specific concentration level will effect an individual is determined by a wide variety of factors including: age, air temperature, health, humidity, personal susceptibility, and more. The following values are general guidelines for lease pumpers to keep in mind.

To ensure you use the proper tools, lease pumpers can also use exposure monitors to measure the contamination levels (see Figure 1).

Figure 1 Exposure meters used for hydrogen sulfide. (courtesy Mine Safety Equipment Co.)

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What Safe Working Procedures Should be Followed in Gaseous Areas?

Whenever a situation arises for lease pumpers to go into a gaseous area alone, there are certain precautions they should use; and since there is no backup, they should take even more measures to ensure their personal safety. For example, first and foremost, you should always check your equipment and make sure it is on (see Figure 2) and operating correctly before entering the contaminated region; and the lease pumper should continue wearing the breathing apparatus until they exit the area.

Figure 2 Example of safety equipment — a warning gate indicating the existence H2S, and that a breathing apparatus is required to proceed.

There are also plenty of different hydrogen sulfide safety training courses available for lease workers, and everyone should take the time for these courses. This official training will help result in a better understanding of the material than if you had read the information in a pamphlet. Plus this will also give the lease pumper valuable experience and training with 30-minute backpacks, 5-minute emergency escape pack, exposure recorders, H2S detectors, monitors, safety equipment, a variety of situations you will rarely see working in the field, and valuable advice from those who have experienced different things.

Remember: when working in a group, only one person will be required to have this formal training. However, it is important for any lease worker who has the chance of working alone on the lease to complete these safety preparation courses.

Where Will A Lease Pumper Encounter Hydrogen Sulfide?

Lease workers can come into contact with H2S almost anywhere on the lease. This can include areas such as:

· Acidizing Wells

· Closed Tanks and/or Vessels

· Contaminated Sulfur

· Drilling Muds

· Gauging Tanks

· Injection of Sour Gas

· Pits and/or Low Areas on Still Days (see Figure 3)

· Tank Bottoms

· Vapor Recovery Units

· Water Injection

Figure 3 Windsocks are often used on sites to show the wind direction and to determine whether it is likely for a H2S buildup.

What Type of Breathing Apparatus Should a Lease Worker Use?

When working in the field, there are times when it is essential to have some form of fresh air available. These fresh air systems used by lease workers can range from fairly simple devices to very elaborate ones. Although the most common system is a portable air pack; some companies or lease owners are known to use industrial size fresh air bottles strapped to a truck bed with a long hose on a reel or other measures. Whatever type you choose, in order for the device to continue to save lives, you always need to properly use and care for your safety gear.

· 5-Minute Air Packs

One of the most widely used and recognized safety backup systems is the five-minute air pack (see figure 4). This device can be used for an emergency escape; including areas where air packs may only be slightly needed. Any instance where the lease pumper is being continuously fed air through a hose; the worker should wear a five-minute air pack for emergencies. Workers should also carry backup systems whenever working in areas more than a few seconds away from safety.

Figure 4 A service bench with 5-Minute Air Packs and 30-Minute Backpacks. (courtesy Marathon Safety Department, Iraan, Texas)

· 30-Minute Backpacks

Another widely used option is the 30-minute fresh air unit (see Figure 4). This breathing apparatus is highly recommended because it can be quickly gauged and generally lasts a week or longer before needing refilled. The device comes in a form-fitting box, and it should be stored there whenever it is not in use. The worker should also:

o Carry a few essential replacement parts (such as the spider or head strap),

o Always keep the device (and the box) clean,

o And if the pack ever breaks a strap, always replace it before wearing it again.

· Compressing Fresh Air (Models using Large Industrial Size Bottles)

These air bottles can typically be refilled at most town fire stations for a fee. Nevertheless, in areas where large amounts of fresh air are consumed, you will also find a variety of companies providing this refill service. In most cases, when a company consumes large quantities of fresh air, the owner(s) will install some form of their own refilling equipment (see Figure 5), such as a compressor. The compressor uses the surrounding air to refill the bottles by first compressing the air, then injecting the air into a series of industrial sized bottles. This acts as an oxygen volume tank to help reduce the time needed to refill the bottles later on.

Figure 5 A compressor used to fill fresh air tanks. (courtesy Marathon Safety Department, Iraan, Texas)

When filling these bottles, it is common to generate heat. As a result, the bottles are often submerged in water while they are being refilled. 30-minute bottles are also branded with a date, and it is required for them to periodically be checked. In addition, these bottles are illegal to refill after a set amount of time has passed, and each bottle is to be replaced with one meeting the proper inspection tests.

When large amounts of air are required, industrial-sized bottles (see Figure 6) with an air line and face mask are often required. These can be rigged up in a variety of ways; from the tank battery to the bed of a pickup truck.

Figure 6 Industrial-sized bottles waiting to be filled with fresh air. The water tank on the left is where the small air tanks are cooled during the refill process. (courtesy Marathon Safety Department, Iraan, Texas)

In most cases, an industrial-sized air tank is too large and heavy to tote around and carry. Typically an air hose is used to transfer air from the bottle to the user, with a fresh air mask being utilized by each person breathing the air (see Figure 7). Typically the tank is just on stand by; and if a warning alarm or horn goes off detecting gas, the masks will be used wigging up to kill the well again. Sometimes when pulling wells or when workers are cleaning tanks, all crew members will be breathing air through hoses and masks.

Figure 7 A lease worker using an industrial-sized air tank with an air mask, and a 5-minute escape pack for emergencies. (courtesy Mine Safety Appliance Co.)

· Trailer-Mounted Standby Units

Industrial-sized air tanks can be used in two different ways. It can be mounted to the bed of a pickup with a reel hose, or it can be installed on the ground at the end of a walkway. This type of air tank is often selected for cleaning tanks, new construction, well servicing, and other jobs onsite (see Figure 8).

Figure 8 Trailer Mounted Fresh Air Devices (courtesy Marathon Safety Department, Iraan, Texas)

Whether you use a trailer mounted fresh air device or a 5-minute emergency air pack, you should always take care of your breathing apparatus. You can learn a lot about an employee based on how they use and take care of their equipment. For instance, visually inspecting the breathing apparatus and looking at the bottle’s refill schedule can indicate a great deal.

As soon as a lease pumper receives his breathing gear, they should first inspect it, put it on, adjust it to fit properly, open the valves, set the rate, and find out if the device works in a satisfactory manner. Generally the device will use quick connect fittings to buckle on, the settings will remain as is, until they are adjusted again. Therefore, when a supervisor checks the equipment and finds the apparatus still wrapped as it was when it was shipped, it is obvious the lease pumper has not been using it.

Remember: Breathing equipment may be expensive, but it provides an invaluable service when properly cared for and maintained; and after each use, the lease pumper should take a few moments to clean and properly store this life saving equipment.

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