Hydrogen Sulfide SafetyHydrogen Sulfide Safety

Etech Environmental & Safety Solutions, Inc.

ObjectivesObjectives 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…ContinuedObjectives…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 PropertiesPhysical Properties

Odor:Similar to rotten eggsCan be detected by smell at less than ¼ of 1 part per millionNo smell at high concentrations

NeverNever trust your sense of smell as the detection method for H2S

SourceSource

H2S is caused by the decomposition of organic material (animal and/or vegetable)

Is found in:Natural GasProduced OilSewers & swampsOther industrial processes

Chemical FormulaChemical Formula

Is comprised of 2 parts hydrogen and 1 part sulfur

Simple compound

Hydrogen and sulfur will readily combine

Hydrogen Atoms

Sulfur Atom

Vapor DensityVapor Density

Colorless, heavier than air (VP = 17.6 atm)Will settle into low spotsEasily dispersed by wind or air currents

AvoidAvoid low-lying areas where H2S is present

Boiling PointBoiling Point

Will boil at –76o f

Has to be below -76o f to become a solid

Will likely be encountered as a gas

Explosive LimitsExplosive 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 awaywell away from any exhaust sources of H2S

PPM vs PercentPPM 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%

SolubilitySolubility

Is readily soluble in water

Can be found in water handling systems of separation processes

Will stay in solution if not treatedIs mechanically treated via heat or agitation

Auto-IgnitionAuto-Ignition

Will spontaneously ignite and burn at 500o fNatural gas has a higher auto-ignition temperature

Do not smoke or use an open flame in the presence of H2S

MetalsMetals

Highly corrosive to certain metals

Causes hydrogen embrittlement (sulfide stress cracking)

Failure is often abrupt

When BurnedWhen Burned

Produces a blue flameGives 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 HazardsPhysiological Hazards

ToxicityIs more toxic than Carbon MonoxideNearly as toxic has Hydrogen Cyanide

Physiological Hazards…ContinuedPhysiological 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…ContinuedPhysiological 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)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 ToxicitySO2 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 healthSource: NIOSH

How H2S Affects IndividualsHow H2S Affects Individuals

Routes of Exposure:LungsEyes (Irritant)

Target Organs:BrainEyesLungs

How H2S Affects IndividualsHow 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 ExposureSymptoms 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 MetalEffects 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

DetectionDetection

Colormetric TubesReact with H2S to change color in the tube media

Direct Reading InstrumentsPersonalAreaRemote

NeverNever trust your sense of smell for the detection of H2S!!!

ReportingReporting

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

RescueRescue

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 neededBeware that higher concentrations may be in the victim lungs

Basic H2S Safety RulesBasic 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 dailydaily

Do not depend upon your sense of smell to detect H2S

Basic H2S Safety Rules…

Continued

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-windcross-wind when exiting an H2S release

Get victim to medical attention immediately

Basic H2S Safety Rules…

Continued

Basic H2S Safety Rules…

Continued

Park your vehicle headed “outout”

Check your protective equipment dailydaily

Keep protective equipment in good operating condition

Report any leaks or suspicions of H2S presence to your supervisor immediatelyimmediately