Working on an oil & gas site can be dangerous in many ways. This is why there is an abundance of procedures and protocols in place for accident prevention. In this blog, we are going to hone in on safety gear and protocols specific to working with H2S, as this directly affects many of our clients and our field service team.
What is H2S?
H2S is the formula for the chemical compound, Hydrogen Sulfide. Gas with H2S, also known as acid gas or sour gas, is commonly found throughout the production stages of crude oil and natural gas.
Hydrogen sulfide is a colorless gas that puts off a rotten egg smell that is not pleasant to be around. It is also extremely hazardous, flammable, corrosive, poisonous, and explosive. Simply from the other names, H2S has been given, it is obvious that it is not the most liked of gases. Some names include swamp gas, manure gas, and sewer gas. Hydrogen sulfide is produced by breaking down bacteria of organic materials and animal wastes when oxygen is absent. H2S is present in places such as swamps, sewers, volcanic gases, well water, and natural gas.
Why is it dangerous?
Remember earlier we mentioned that H2S has a rotten egg smell? Well, this is true when the levels are at low concentrations. When hydrogen sulfide is continuously exposed at high concentrations, a person loses their ability to smell and therefore can no longer smell the rotten odor making it hard to identify H2S without a gas monitor. According to OSHA, the offensive smell begins to change at 30 ppm (parts per million) of H2S and by 100 ppm an individual sense of smell could dissipate within minutes of exposure.
Levels above 100 ppm can cause immediate risks. These high concentrations of H2S can cause shock, convulsions, loss of the ability to breathe, unconsciousness, coma, and death. Moderate levels of exposure can cause eye irritation, breathing difficulty, dizziness, headaches, vomiting, and coughing. Lower levels can cause respiratory system irritation, irritation of eyes, nose, and throat. It also can cause shortness of breath. These symptoms can last anywhere from a couple of hours to several days.
Visit OSHA’s website for a full list of signs and symptoms that come with with different levels of H2S concentration.
Protect Personnel & Equipment
H2S is clearly something that should be taken seriously. There are steps that OSHA states very clearly on how to avoid situations like above. Take a look at the image to the right. These are OSHA’s recommended steps to be sure you limit the risk of involving yourself in a dangerous situation when encountering H2S. Like I mentioned above, H2S can be present in natural gas. In the oil & gas industry, it is sometimes a risk that H2S be present at well sites or treatment facilities. In this case, H2S is also called sour gas.
Wearing a proper H2S detection monitor can help detect the levels of H2S so you know when it is and is not safe. For general industry regulations of exposed H2S levels, OSHA states, “Exposures must not exceed 20 parts per million (ppm) (ceiling) with the following exception: if no other measurable exposure occurs during the 8-hour work shift, exposures may exceed 20 ppm, but not more than 50 ppm (peak), for a single time period up to 10 minutes.”
If you happen to be in a situation where there are increased levels of H2S released, remember to escape upwind and uphill if available. Try to determine where the source is coming from and be sure to go around it.
H2S can also be a risk for your production equipment and piping. The corrosive effects of H2S can quickly ruin equipment and create severe maintenance headaches. Effective H2S removal with equipment such as an amine plant or chemical injection system is essential to natural gas production operations. At CROFT, we understand the risks and obstacles when it comes to H2S and we can help you determine the safest and most efficient method for H2S Removal.
*Updated May 2020 by a CROFT Representative