How to Check for Hydrogen Sulfide

The concentration of a gas in air can be measured in parts per million, or ppm.

Hydrogen sulfide, or H2S, is a colorless, flammable, toxic gas found in hot springs, volcanoes, natural gas wells, mines, sewers, paper mills and other manufacturing plants. A few breaths of air containing hydrogen sulfide at a concentration of 500 parts per million, or ppm, can cause death. At a concentration of 10 ppm, hydrogen sulfide exposure causes irritation of the eyes, nose and throat. At a concentration of 10 ppm to 50 ppm, exposure causes dizziness, headache, nausea, vomiting and breathing difficulty. Hydrogen sulfide gas has a very distinct odor at certain concentrations, and you can use a gas monitor to detect hydrogen sulfide.

Things You'll Need

• Gas monitor

Instructions

Smell

1. Inhale normally and take note of any odor present. If you smell an odor like rotten eggs, there may be hydrogen sulfide gas present in the air at a concentration of up to 30 ppm. At a concentration of 30 ppm to 100 ppm, hydrogen sulfide gas has a sickeningly sweet odor.

2. Leave the area immediately if you smell these odors or experience any of the symptoms of hydrogen sulfide gas exposure.

3. Wear protective gear and communication equipment if you return to the area. Ventilate the area containing the hydrogen sulfide gas if possible.

Gas Monitor

1. Turn on the gas monitor by pressing the "On/Off" button. The pilot light should light up indicating that the device has power, and the display screen will turn on.

2. Verify air is entering the device. Block the tube that air enters through with your thumb. The reading on the display screen should indicate reduced airflow. Remove your thumb.

3. Press the "Menu" button and select hydrogen sulfide gas to set your multiple gas monitor to detect hydrogen sulfide gas. Skip this step if you are using a single gas monitor designed to detect hydrogen sulfide gas.

4. Hold the monitor in an area that you wish to test for hydrogen sulfide gas. Read the display screen to check the concentration of hydrogen sulfide gas present.

5. Leave the area immediately if any of the alarms trigger. A gas monitor usually has three alarms. The screen will indicate high hydrogen sulfide gas concentration and an audio alarm will sound. It also has a vibrating alarm for use in high noise areas.

Tips & Warnings

• Make sure you use the hydrogen sulfide indicator if you use a single gas monitor.

• Do not rely on your sense of smell alone. Long exposure to hydrogen sulfide or exposure to concentrations of hydrogen sulfide above 100 ppm can lead to a temporary loss of the sense of smell.

References

• Agency for Toxic Substances and Disease Registry; ToxFAQs for Hydrogen Sulfide; 2006
• SafetyDirectory.com; H2S Safety Factsheet; 2004
• RKI Instruments; Sample Draw Hydrogen Sulfide Gas Detector for Use With Generic Device; 2011
• RKI Instruments; GX-2009; 2011
• JJS Technical Services; Gas Alert Extreme Single Gas Monitor; 2011
• Occupational Safety and Health Administration; Fact Sheet: Hydrogen Sulfide (H2S); 2005