Hydrogen Sulfide (H2S) Safety

Hydrogen sulfide is an extremely hazardous gas with the distinctive odor of rotten eggs. It is colorless and very dangerous when high concentrations are inhaled. Hydrogen sulfide is highly flammable and explodes easily near lit matches, cigarettes, and other sources of spark or heat.

Hydrogen sulfide is heavier than air and can collect in enclosed areas like basements, manholes, sewers, and manure pits. Hydrogen Sulfide presents a particular hazard to those working in confined spaces at or below ground level because it is a naturally occurring hazard.

Hydrogen sulfide is of special concern because it is a hazardous by-product of industrial processes in the petroleum, pulp and paper, and construction industries, and may also be present on active sanitary landfills and in sewers and sewage treatment plants.

Hydrogen sulfide can be acutely toxic and cause serious damage to your body, or even death, within a very short period of time after exposure.

How do safety professionals mitigate the risk of hydrogen sulfide gas?

A qualified person will use a gas-specific meter or monitor to check for the presence of hydrogen sulfide in your workplace. To ensure your safety, do not enter a workspace until it has been properly tested.

Engineering controls are the mechanical means to control the hazard at its source and are the preferred way to protect against hazards. Engineering controls are designed to eliminate the hazard completely, if possible. The primary engineering control used in eliminating hazardous gases is a non-sparking exhaust and ventilation system that prevents the build-up of hydrogen gas.

If a hazard cannot be eliminated using engineering controls, administrative controls are added to the hazard-control strategy. Administrative controls are a company’s rules and procedures put in place to protect the health and safety of the workforce. Examples of administrative controls include a written exposure plan, posted warning signs, a rescue plan for hydrogen sulfide exposure, and workplace safety training.

If engineering and administrative controls are not possible or are not fully effective, you may be required to use personal protective equipment (PPE). This would include respiratory equipment, eye protection and special gloves and clothing if skin contact is possible.

Inhalation is the primary exposure method of hydrogen sulfide. In the event of inhalation exposure, call 911 immediately. Follow rescue procedures and enter the affected area only if trained to do so and it is safe to enter. Immediately transfer the affected person to a medical facility.

If you or a co-worker’s eyes are exposed to hydrogen sulfide, remove contact lenses if worn, wash the eyes with plain water for 15 minutes, making sure to lift the eyelids, and seek immediate medical attention.

If you or a co-worker’s skin is exposed to hydrogen sulfide, wash the exposed skin immediately, soak contaminated clothes and shoes with water before removing them, wash the skin that was covered by clothing and shoes, and seek immediate medical attention.

If you encounter a fire involving hydrogen sulfide, call 911 immediately. Follow fire response and emergency evacuation procedures.