Hydrogen Sulfide Safety Reading

Hydrogen sulfide flammable, colorless gas (H2S) that is toxic at extremely low concentrations.  It is heavier than air and may accumulate at low lying areas.  It smells like “rotten eggs” and causes you to quickly lose your sense of smell.

Exposure can cause several adverse health effects:

• irritation of the eyes, nose, and throat
• respiratory problems at low concentrations
• severe nausea
• convulsions
• coma
• even death at high concentrations

The colorless gas occurs naturally in crude petroleum and natural gas and also can be produced by the breakdown of organic material in sewage.

It is particularly dangerous in poorly ventilated confined spaces such as basements, manholes and underground utility vaults.

When working in areas that contain the Hydrogen Sulfide chemical the employer should develop and implement an H2S contingency plan which should include:

Have a qualified person test the air for hydrogen sulfide.

If the gas is present, ventilate the space with an intrinsically safe ventilator.

Because the gas is also highly flammable, determine whether fire or explosion precautions are necessary.

If the hydrogen sulfide cannot be removed the space must be “permitted”, use appropriate PPE such as respiratory protection and rescue equipment.

Concentration levels of 300 parts per million are considered immediately dangerous to life and health, and self-contained breathing apparatus is required.

Concentration levels of 100 parts per million or more are considered the point where the smell of the chemical may be paralyzed due to it killing the olfactory nerve.