Hydrogen Sulfide Safety Etech Environmental & Safety Solutions, Inc.

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

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

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

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

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

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

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

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

PPM vs Percent To convert parts per million (ppm) to percent, move the decimal 4 places to the left: 1 ppm = .0001% 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%

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

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

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

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

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

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

Physiological Hazards…Continued Typical Body Responses (Continued) 200 - 300 ppm Marked conjunctivitis and respiratory tract irritation 500 - 700 ppm Loss of consciousness & possible death 700 - 1000 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

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

SO2 Toxicity 3-30 ppm Slight respiratory irritation 30-50 ppm Altered sense of smell & taste, increased fatigue 50-100 ppm Maximum permissible exposure for ½ hour 200-400 ppm Intolerable by humans, could lead to serious illness or death 400-500 ppm Immediately dangerous to life and health Source: NIOSH

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

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

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

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

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!!!

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

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

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

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

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