What is H2S? Facts, Risks, and Effects in Industrial Workplaces

H2S, also known as hydrogen sulfide, is a colourless gas that, unfortunately, can go unnoticed until it’s too late.

At very low concentrations, this toxic gas has a distinct odour of rotten eggs, however, at high concentrations, it is usually undetected by the human nose due to rapid olfactory desensitization, which is when the sense of smell becomes less sensitive or completely desensitized to an odour.

This gas is commonly found in natural environments such as hot springs, swamps, and marshes, but it is also a byproduct of many industrial processes, including pulp and paper operations, oil and gas facilities, wastewater treatment systems, and livestock operations.

Because exposure to hydrogen sulfide can cause serious short-term and long-term effects, and even death, it is crucial for workplaces to implement effective safety measures to minimize risk.

To better understand how you can protect yourself and others, especially in industrial work environments, follow along as we dive into the facts, effects, and risks of hydrogen sulfide.

What Are the Short-Term Health Effects of H2S Exposure?

Exposure to hydrogen sulfide, even for short periods, can have immediate and severe health effects.

At low concentrations, individuals exposed to this highly toxic gas are likely to experience:

• Irritation of the eyes, nose, and throat
• Coughing and shortness of breath
• Headaches and dizziness
• Nausea and vomiting
• Fatigue

High concentrations of hydrogen sulfide are particularly dangerous, as they can cause more pronounced and severe health issues, including shock, convulsions, the inability to breathe, and death within minutes of exposure.

What Are the Long-Term Health Effects of H2S Exposure?

Prolonged exposure, even at low levels, can lead to serious long-term health implications.

Individuals continuously exposed to hydrogen sulfide may experience prolonged eye irritation and inflammation, as well as recurrent headaches and dizziness.

Additionally, their symptoms could include:

• Respiratory issues such as chronic bronchitis
• Neurological effects such as memory loss and poor motor function
• Eye damage
• Skin problems
• Cardiovascular issues
• Gastrointestinal distress
• Weakened immune system

These potential health effects solidify the importance of monitoring and controlling hydrogen sulfide levels in industrial environments.

What Treatment Is Necessary After H2S Exposure?

If exposure occurs, H2S emergency personnel should be called because prompt medical treatment is required to help mitigate potential health effects and prevent death.

To reduce further exposure, it’s helpful to remove the affected individual to somewhere with fresh air. If the individual is having trouble breathing, they should be given emergency oxygen, and if they have stopped breathing, they should receive cardiopulmonary resuscitation (CPR). Additionally, removing contaminated clothing can reduce exposure. These items should be double-bagged, sealed, and labelled for the safety of everyone involved.

If there is irritation to the individual’s eyes, they should be flushed with lukewarm, gently flowing water for 15-20 minutes.

In severe cases where loss of consciousness or convulsions occur, advanced medical interventions, such as intravenous fluids, may be necessary.

Continuous monitoring is also essential, as some symptoms of hydrogen sulfide exposure may take time to develop.

What Are the Exposure Limits of H2S?

To protect workers from both acute and chronic health effects of hydrogen sulfide exposure, the federal government has set exposure limits.

The occupational exposure limit (OEL) is 10 parts-per-million as an eight-hour time-weight average (TWA), and the short-term exposure limit (STEL) is 15 ppm for a 15-minute period, according to the Canadian Centre for Occupational Health and Safety (CCOHS).

These exposure limits are part of occupational safety regulations that help ensure that workplaces have effective monitoring, ventilation, and personal protective equipment. By adhering to these limits, employers can significantly reduce the risk of H2S-related health issues and create a safer work environment for their employees.

How Do You Detect H2S?

Because people cannot safely rely on their sense of smell to detect hydrogen sulfide gas, it is crucial to use other detection methods for the safety and health of every person at an industrial site.

One of the most common ways to detect hydrogen sulfide is by using fixed gas detectors, which should be placed near the ground because H2S is heavier than air. These detectors provide continuous monitoring, ensuring there is an immediate alert if the toxic gas is present.

There are also portable gas detectors for workers to carry with them while on shift, ensuring they are notified if they are being exposed to hydrogen sulfide. These detectors have a digital screen that shows the current H2S concentration, allowing employees to easily check if they are concerned for their safety.

How Do You Protect Against H2S Exposure?

Although hydrogen sulfide is extremely dangerous, there are fortunately ways to protect individuals from exposure.

The key strategies to ensure occupational safety from H2S include:

• Installing ventilation systems to disperse and remove hydrogen sulfide from work areas
• Using fixed and portable gas detectors to continuously monitor hydrogen sulfide levels and provide early warning of hazardous concentrations
• Developing and practicing emergency response plans, including evacuation routes and procedures for dealing with hydrogen sulfide leaks or spills
• Providing comprehensive training for workers who may be exposed to hydrogen sulfide
• Labelling areas where hydrogen sulfide may be present
• Using personal protective equipment, such as chemical-resistant clothing, gloves, and eye protection

By combining these preventive measures, workplaces can improve safety and protect employees from toxic substances.

Fast Facts About H2S

Because hydrogen sulfide is one of the most common chemical hazards in industrial settings, it’s understandable why there are so many frequently asked questions about it.

Below is a quick summary of what the majority of people are curious to know:

• Is H2S heavier than air? Yes, which is why it tends to accumulate in low-lying areas.
• Is H2S flammable? Yes, so it’s important to be extra cautious of flammable items in environments where hydrogen sulfide is present.
• Is H2S odourless? While it has a characteristic odour of rotten eggs, people often cannot smell hydrogen sulfide because it paralyzes the olfactory nerve.
• Is H2S toxic? Yes, even very low concentrations of hydrogen sulfide are toxic.
• Is H2S an acid? Yes, hydrogen sulfide is considered a weak acid when it’s dissolved in water.
• How deadly is H2S gas? Hydrogen sulfide is extremely deadly, as it can cause death within minutes.
• Why is H2S dangerous? Hydrogen sulfide is dangerous because it is hard to detect without the proper equipment, and symptoms of exposure can be fatal.
• Where is H2S found? Hydrogen sulfide occurs naturally in environments such as hot springs, swamps, and marshes, but it is also found in industrial settings because it is a byproduct of various industrial processes, including oil refining, mining, pulp and paper processing, and food processing.
• What is H2S used for? Hydrogen sulfide can be used to extract metals from ores and modify soil properties.

How Can You Protect Your Crew?

At Trojan Safety, we have more than 30 years of industrial safety expertise to support your business.

As a leading H2S Safety Services provider for emergency response, critical sour drilling, and completion operations and plant turnarounds for the oil and gas industry in Western Canada and the territories, we are dedicated to keeping your crew safe while the threat of hydrogen sulfide is present.

Additionally, we offer H2S Alive training for oil and gas industry workers. Our all-day training session covers:

• Health hazards, properties, and probable locations of H2S
• Hazard assessments and controls
• Respiratory protective equipment
• Detection devices
• Initial response procedures and strategies for H2S emergencies

Contact us to learn more about how to make your industrial operations safer.