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Three Dangerous Gases in Confined Spaces

Contributor: Gas Clip Technologies

Everyone has heard the line, “What they don’t know won’t hurt them.” It is a lie that people frequently use as an excuse to keep something secret. However, the truth of the matter is that what a person does not know is usually what hurts them in the end, particularly in confined spaces. The atmosphere in those areas can make breathing dangerous if not fatal due to the types of gases that can potentially fill the air, such as hydrogen sulfide.

Hydrogen Sulfide (H2S)

This highly toxic gas is commonly produced by different industrial processes, such as petroleum extraction, agricultural silos, and even food processing. However, it is also frequently found in nature, particularly wherever decomposition is prevalent—such as in marshy landscapes, hot springs, and manure pits.

Should a worker be exposed to hydrogen sulfide, the side effects depend on the duration of exposure and the amount of gas present. For example, at 0.01 – 1.5 ppm, the gas smells like rotten eggs; and as long as everyone leaves the area as soon as it is detected, no permanent harm is done. If the amount of gas is higher or the exposure longer, then over time the employees could experience eye irritation, headache, nausea, loss of smell, and other symptoms of varying degrees. Unfortunately, if the amount of hydrogen sulfide hovers around 1000-2000 ppm, death is almost instantaneous.

Carbon Monoxide (CO)

Another common and equally dangerous gas is carbon monoxide. It is odorless, tasteless, colorless, and can be found wherever fossil fuels are burned—such as in vehicles and certain power tools. Workers die every year because they use that type of equipment without proper ventilation—a circumstance that greatly increases during the winter months. Employees inevitably create a confined space by closing all the doors and windows to keep the area warm; and without a reliable gas detector, they cannot properly monitor the fumes created by their equipment.

Like hydrogen sulfide, the side effects of exposure to carbon monoxide vary based on duration and the amount of gas present. For example, 0.5 – 5 ppm is the typical amount that one would find outdoors in a major metropolitan area and carries little to no risk of side effects. However, if an individual spent 8 hours in a confined space where the gas level sat at 50 ppm, they could expect to have a headache and dizziness. Once the carbon monoxide level reaches 6,400 ppm, a person would be unconscious after two or three breaths and dead within 15 minutes.

Oxygen (O2)

As awful as the side effects are for both carbon monoxide and hydrogen sulfide, the real root of the problem is that they both displace the oxygen in the air and thereby poison the exposed individual’s blood. On the other hand, having too much oxygen in an area’s atmosphere can be equally as dangerous. Breathable air is generally 20.8% – 21% oxygen. However, if that gas rises above 22%, the atmosphere becomes explosive. This situation can be created by various chemical reactions, a leaking oxygen hose or even a liquid oxygen spill.

Fortunately, breathing oxygen-enriched air does not cause any adverse effects in the short term. However, if one does it for an extended period, the alveoli in their lungs can collapse. The patient can also experience retinal detachment and even seizures. Recovery is possible once the individual’s oxygen levels return to normal.

Safe Practices

All-in-all, the best way to keep oneself safe when entering a confined space is to follow the motto of scouts worldwide—be prepared. Have a plan that addresses what to do if the atmosphere is already dangerous before entering the area as well as one for if workers are already in a space when the atmosphere becomes precarious. Both cases require testing and continual monitoring via a certified gas detector or pump, such as the MGC Pump from Gas Clip Technologies. Lastly, never enter a confined space without someone on site who knows the emergency plan and can execute it should the situation turn dangerous. Life is too precious for reckless decisions, so treat it with care. Take precautions and remain aware.

About the Author

Gas Clip Technologies is a Texas-based international company founded on returning safety, simplicity, reliability, and customer satisfaction to the gas detection business. Their focus from the beginning has been on one thing—designing and manufacturing simple to use portable gas detectors that save precious time, resources, and lives.

Gas Clip Technologies specializes in compliance-based detectors that are customizable, durable, dependable, and user-friendly with a low cost of ownership. 100% of their detectors are quality tested to eliminate downtime and expenses that can occur due to detector malfunction.

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Attending VPPPA’s 2022 Safety+ Symposium? Stop by booth #733 to connect with the Gas Clip Technologies team and hear more about how they can solve your gas detection problems.

Jacqueline "Jackie" Annis is an industrial hygienist with the Office of Partnerships and Recognition, Directorate of Cooperative and State Programs in OSHA’s National Office.  Jackie’s primary responsibilities include developing and overseeing internal policies and procedures for the VPP, reviewing VPP on-site evaluation reports for process safety management information, serving as the National Office liaison for two of OSHA’s ten Regions, and facilitating the management of OSHA’s National Strategic Partnership Program.  She is an integral part of OSHA’s National Office team. 

She has served with the Agency for 36 years, including five years as a senior industrial hygienist in OSHA’s Office of Health Enforcement, Directorate of Enforcement Programs in the National Office and 17 years as a compliance safety and health officer in the Denver, CO Area Office.  Prior to her tenure at OSHA, Jackie worked as an industrial hygienist for the Department of the Navy in Alameda, California.  Jackie obtained a Bachelor of Science degree from Old Dominion University in Norfolk, VA in 1983.

Wayne Howard earned a B.S. in Chemical Engineering from UC Davis and has spent 12 years with Shell (at Martinez) refinery, 3 years with the consulting firm Process Safety, 15 years with Valero (at Benicia), and the last 10 years in the Corporate Process Safety Department. He is the Valero representative to AFPM's Advancing Process Safety Initiative.

Nathan Obaugh, PE is a senior engineer in the Safety and Operational Excellence Group at NuStar Energy. Nathan has over 10 years of PSM and process design experience in the petrochemical, refining and midstream industries. At NuStar, Nathan oversees all elements of the corporate PSM program and works directly on hazard analysis, process safety studies, PSM/RMP audits and provides process engineering support to the operations and capital projects groups.

Jared Teter, PhD is a senior staff scientist with a background in physics and hazards analysis. He has extensive experience in subscale testing of energetic materials and has served as program manager for several large testing and risk management projects. He has applied engineering and risk management protocols while evaluating the risk associated with propellant and explosives manufacturing, combustible dust, and other hazardous material related processes.

Tim Belitz has a degree in Environmental Health/Industrial Hygiene from Old Dominion University and a Master’s from Duke University. He has over 25 years of Industrial Health Safety and Environmental Experience and is a Certified Safety Professional. He has many years focused on Contractor Management and Process Safety programs.

Rob Walker graduated from Virginia Tech in Microbiology and Chemical Engineering. Rob has almost 35 years of experience working in the chemical plant and refining industry. His passion for Process Safety and Mechanical Integrity began very early in his career. Rob began with his current company, Honeywell, back in 2011.

Prasad Joshi has B.S. and M.S. Degrees in Chemical Engineering from two universities in India. Prasad has over 30 years’ experience in the business. He began with Honeywell in May 2022 as Principal Maintenance Engineer. He has worked internationally in Asia and Europe.