1. Hydrogen Sulfide Safety
Etech Environmental & Safety Solutions, Inc.

2. Objectives At the completion of this class, students will be able to:
Recognize the potential for exposure and the characteristics of H2S
Understand and describe the effects of H2S on humans and metals
Identify the presence of H2S and understand the use of appropriate protective measures

3. Objectives…Continued
Understand basic notification procedures
Understand the basic use of detection equipment
Understand basic rescue and safety measures
Demonstrate the correct use of protective equipment
Meet the certification requirements for H2S training

4. Physical Properties Odor:
Similar to rotten eggs
Can be detected by smell at less than ¼ of 1 part per million
No smell at high concentrations
Never trust your sense of smell as the detection method for H2S

5. Source
H2S is caused by the decomposition of organic material (animal and/or vegetable)
Is found in:
Natural Gas
Produced Oil
Sewers & swamps
Other industrial processes

6. Chemical Formula Is comprised of 2 parts hydrogen and 1 part sulfur
Simple compound
Hydrogen and sulfur will readily combine
Hydrogen Atoms
Sulfur Atom

7. Vapor Density Colorless, heavier than air (VP = 17.6 atm)
Will settle into low spots
Easily dispersed by wind or air currents
Avoid low-lying areas where H2S is present

8. Boiling Point Will boil at –76o f
Has to be below -76o f to become a solid
Will likely be encountered as a gas

9. Explosive Limits Has an explosive range of 4.0 - 44%
Explosive range for gasoline is 1.5 – 7.6%
Can dramatically increase the volatility of natural gas
Park your vehicle well away from any exhaust sources of H2S

10. PPM vs Percent
To convert parts per million (ppm) to percent, move the decimal 4 places to the left:
1 ppm = % or 1/10,000 of 1%
10 ppm = .001% or 1/1,000 of 1%
100 ppm = .01% or 1/100 of 1%
500 ppm = .05% or 5/100 of 1%
1000 ppm = .10% or 1/10 of 1%
10,000 ppm = 1%

11. Solubility Is readily soluble in water
Can be found in water handling systems of separation processes
Will stay in solution if not treated
Is mechanically treated via heat or agitation

12. Auto-Ignition Will spontaneously ignite and burn at 500o f
Natural gas has a higher auto-ignition temperature
Do not smoke or use an open flame in the presence of H2S

13. Metals Highly corrosive to certain metals
Causes hydrogen embrittlement (sulfide stress cracking)
Failure is often abrupt

14. When Burned Produces a blue flame
Gives off sulphur dioxide (SO2)
Is very toxic
Methane based natural gas produces a yellow to orange flame
Neither methane gas or H2S will create smoke

15. Physiological Hazards
Toxicity
Is more toxic than Carbon Monoxide
Nearly as toxic has Hydrogen Cyanide

16. Physiological Hazards…Continued
Typical Body Responses
0.13 ppm Minimal perceptible odor
4.60 ppm Easily detectable, moderate odor
10 ppm Beginning of eye irritation
27 ppm Strong, unpleasant odor
100 ppm Coughing, eye irritation, loss or sense of smell
Source: ANSI

17. Physiological Hazards…Continued
Typical Body Responses
(Continued)
ppm Marked conjunctivitis and respiratory tract irritation
ppm Loss of consciousness & possible death
ppm Rapid unconsciousness, cessation of respiration, death
1000 – 2000 ppm Unconscious at once, death may occur even if the victim is removed to fresh air at once
Source: ANSI

18. Sulphur Dioxide (SO2) By product when H2S is burned Heavier than air
Colorless
Lethal at high concentrations
In the presence of moisture forms a mild sulphuric acid
Readily dispersed by wind & air currents

19. SO2 Toxicity 3-30 ppm Slight respiratory irritation
30-50 ppm Altered sense of smell & taste, increased fatigue
ppm Maximum permissible exposure for ½ hour
ppm Intolerable by humans, could lead to serious illness or death
ppm Immediately dangerous to life and health
Source: NIOSH

20. How H2S Affects Individuals
Routes of Exposure:
Lungs
Eyes (Irritant)
Target Organs:
Brain
Eyes

21. How H2S Affects Individuals
Other Factors:
Duration (Length of exposure time)
Intensity (Level of concentration)
Individual Susceptibility (Each individual reacts differently to H2S exposure)

22. Symptoms of Exposure Skin Irritation Eye Irritation Fatigue Nausea
Headache
Loss of appetite
Dizziness
Irrational behavior
Dryness in nose, throat
Coughing
Loss of consciousness
Cessation of all life processes
Symptoms may occur individually or in combination

23. Effects On Metal Higher hardness steel is more prone to embrittlement
Causes stress fractures
Causes Crystallization
Is prone to acid gas corrosion
May form iron sulfide

24. Never trust your sense of smell for the detection of H2S!!!
Colormetric Tubes
React with H2S to change color in the tube media
Direct Reading Instruments
Personal
Area
Remote
Never trust your sense of smell for the detection of H2S!!!

25. Reporting
Report any known presence or suspicions of H2S presence to your supervisor immediately

26. Rescue
Never effect a rescue before first donning proper respiratory protection and calling for assistance
Move the victim to a side wind area safely away from the source
Administer first aid as needed
Beware that higher concentrations may be in the victim lungs

27. Basic H2S Safety Rules
Evacuate if levels of 10 ppm or greater are detected
Use respiratory protection in areas greater than 10 ppm
This level may be greater if dictated by local authority or your
Company’s policy
If you work in an H2S area, make sure respiratory protection is available, check it daily
Do not depend upon your sense of smell to detect H2S

28. Basic H2S Safety Rules…Continued
Always use the “Buddy” system when working in H2S environments
Do not attempt rescue unless you have been properly trained, have first called for assistance and have donned proper respiratory protection
Move cross-wind when exiting an H2S release
Get victim to medical attention immediately

29. Basic H2S Safety Rules…Continued
Park your vehicle headed “out”
Check your protective equipment daily
Keep protective equipment in good operating condition
Report any leaks or suspicions of H2S presence to your supervisor immediately