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Hydrogen Sulfide Gas Toolbox Talk | H2S Gas Hazards and Safety Talk

Hydrogen Sulfide Gas Toolbox Talk | H2S Gas Hazards and Safety Talk
Safety toolbox Talk on Hydrogen Sulfide Hazards and Safety measures

Hydrogen Sulfide Gas Toolbox Talk | H2S Gas Hazards and Safety Talk 

Conducting toolbox talk on Hydrogen Sulfide (H2S) safety is very important in Oil & Gas, mining, peatland, swamp and sewer facilities prior to start any work in an area prone to H2S gas. It is natural gas deposits crude oil and get release during oil exploration and oil refining process.

Hydrogen Sulfide (H2S) is a naturally occurring chemical compound produced during the decomposition of organic matter. It is a highly toxic and flammable gas also recognized as deadliest gas or silent killer.

Toolbox talk is the best tool for communicating identified hazards, risk and safety control measures to the workforce before starting their assigned work. Here you will find H2S hazards, Risks and safety control measures that will help to conduct safety toolbox talk in your workplace.


Hazardous Properties of H2S

H2S gas is highly toxic, extremely flammable, corrosive, colorless, heavier than air, and soluble in both water and oil.

It smells like rotten eggs at lower concentrations, but prolonged exposure reduces the ability to smell and symptoms may be delayed.

It is the deadliest gas that can cause respiratory irritation and fatal if inhaled in high concentrations.

Contact with the liquid can cause cold burn or frostbite.

TLV-TWA is 1 ppm, STEL is 5 ppm, the ceiling value is 20 ppm, and IDLH is 100 ppm.

H2S has a wide flammability limit between 4.3 and 46 Vol%

Exposure can cause mild headaches, eye / nose / throat / respiratory system irritation to very severe, loss of consciousness and death. It is an irritant and chemical asphyxiating, i.e. it has effects on both oxygen utilization and the central nervous system.

As it is heavier than air, it is found in low-lying areas such as pits, sewers, underground vaults, and therefore makes work in confined spaces potentially dangerous.


Hydrogen Sulfide (H2S) Risk

The main route of exposure for H2S is inhalation. Inhaled gas is quickly absorbed into the lungs.

At lower concentrations, people can smell the "rotten egg" smell initially, but with continued exposure, a person loses their ability to smell, also called olfactory fatigue. Therefore, people should not rely on their sense of smell and should leave the area immediately after the first smell.

As hydrogen sulfide gas is heavier than air and highly explosive, the leaking gas can form a vapor cloud and can travel to sources of ignition that can result in the explosion of a vapor cloud. If it ignites, it produces other toxic gases such as sulfur dioxide.

People with asthma can experience breathing difficulties even at low concentrations.

Repeated or prolonged exposures can cause eye inflammation, headache, fatigue, irritability, insomnia, digestive disturbances, and weight loss.

A person exposed to moderate concentrations of H2S can cause severe eye and respiratory irritation, including coughing, headache, dizziness, nausea, vomiting, staggering, excitability, shortness of breath, and fluid build-up in the lungs.

The person exposed to higher concentrations can cause inability to breathe, shock seizures, extremely rapid loss of consciousness, coma and death. Effects can occur in one or two breaths.


Safety precautions for exposure to H2S

Safety precautions for exposure to H2S

Always carry a personal gas monitor / detector and check the location of the wind shocks before entering an area prone to H2S.

Be sure to perform a gas test before entering confined spaces where there is a likelihood of exposure to H2S.

Ensure the provision of mechanical ventilation in all confined area work.

People working in confined spaces or in the area where the possibility of exposure to H2S exists, all people should wear a self-contained breathing apparatus or an air supply line with other appropriate PPE.

An air-purifying respirator with a filter cartridge suitable for H2S can be used if the concentration is less than 100 ppm. A full facepiece respirator should be worn to protect the eyes.

An emergency rescue team and communication system should be established. Never attempt a rescue without wearing proper respiratory protection.

Don't work alone in an H2S-prone area. If you are taking samples in the area of ​​operation, stand on the upwind side of the sampling point.

In the event of a gas leak, evacuate the area immediately from the direction of the crosswind without creating panic and assemble at a safe assembly point. It is not advisable to find the source of the leak without having a SCBA with you.


H2S exposure First Aid measures

Inhalation: Remove exposed person to fresh air. Check for breathing, if person has difficulty breathing, use first aid kit and provide emergency oxygen. If the person is not breathing and is unconscious, give artificial respiration. Avoid mouth-to-mouth resuscitation, better cover your mouth with the appropriate protectors. Seek immediate medical assistance.

Skin Contact: Immediately remove the victim from the source of contamination. Remove contaminated clothing and cover the affected area with a sterile dressing. Seek medical assistance quickly.

Eye Contact: Flush the eyes immediately with plenty of water for 15-20 minutes. Try to open the eyelid to remove the contaminant. Cover both eyes with a sterile dressing. Seek immediate medical assistance.


Toolbox Talk on Hydrogen sulfide (H2S) safety should be held prior to performing any task in an H2S prone area. At the end of the toolbox talk, interactive questions can be asked of the participants to ensure positive feedback and a better outcome.

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