Hydrogen Sulfide Hazard Assessment

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Hydrogen Sulfide Hazard Assessment

• Erik Vermulen
• MSHA, District 9
• Coal Safety and Health
• 303-231-5586

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Hydrogen Sulfide Hazard Assessment

• Introduction
• Occurrence in Mines, Scenarios
• Detection
• Range of Health Effects
• Emergency Actions
• Action Levels

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Hydrogen Sulfide Hazard Assessment

• Occurrence in Mines, Scenarios
• Generated from reduced biomass (coal, natural
  gas, garbage), Geochemical sources in sediments,
  human metabolism
• Released from pockets in coal, natural gas vents,
  supersaturated water
• May be wide spread or localized constant or in
  pockets of varying concentration

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Hydrogen Sulfide Hazard Assessment

• Detection
• Odor lt0.02 ppm none, 0.13 ppm perceptible,
  1.0 ppm - faint, 5 ppm - moderate, 25 ppm
  strong, 100 ppm lose odor in 2-15 minutes
• Electro chemical sensors calibrated and within
  shelf-life
• Detector tubes and Impregnated Paper Within
  shelf-life
• Absorb air samples with analytical determination
• Biological exposure methods for expired air and
  tissues

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Hydrogen Sulfide Hazard Assessment

• Range of Health Effects
• (Concentration Time Effects)
• Death due to respiratory failure with brief
  exposures to very high concentrations (seconds at
  gt1000 ppm)
• Acute intoxication with neurological,
  respiratory, ocular and cardiac symptoms with
  potential recovery (exposures from minutes to
  hours at 250 to 1000 ppm, in animals LC-50 ranges
  from 335 to 587 ppm)
• Sub-Acute and Chronic toxicity include cardiac
  arrhythmia, neuropathology, respiratory
  lesions/edema, blood-enzymes, ocular, cellular
  effects (exposures from 10 200 ppm for hours to
  months)
• Lifetime exposures Carcinogenic, developmental
  - none

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Enforcement Surveys for H2S

• Chapter 4, Health Inspection Procedures Handbook
• Pre-inspection Actions Select method,
  pre-calibration, UMF
• Walk-Through to document process, duration,
  frequency, sketch
• Select maximally exposed occupation (if refuses
  can sample BZ)
• Follow normal 8-hour, portal to portal sampling
• Use Vent Plan method if one is designated, record
  rationale
• With instruments, check periodically, follow/note
  Manuf. instructions
• Place instrument on shirt near breathing zone,
  note location
• Recommend using a second detection method (stain
  tube, Zefluor tube, OSHA ID141) to verify, record
  sample time
• Record miners locations, general duties,
  variance from normal
• Fill out MSHA 2000-187 (MSHA 2000-194 if analysis
  needed)

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Enforcement Surveys for H2S Cont.

• Out-brief miners/operators and notify that a
  citation may be issued if later data analysis
  indicates an over-exposure
• If instrument TLV-TWA, 8Hr, exceeds 5 PPM notify
  operator that corrective action may be required
  no citation issued but Vent Plan change.
• Post Inspection Actions
• Post calibrate instrument or bump test
• Download data using manufacturers software, save
  files
• Evaluated STEL file to see if any 15 minute
  increment gt 20PPM
• Evaluate TLV file to see if 8 hour gt10 PPM
• Contact District for assistance in writing the
  Citation, if applicable
• (Note Instruments not listed by NIOSH or OSHA as
  standard method rationale important)

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Hydrogen Sulfide Hazard Assessment

• Range of Health Effects
• (Receptor Susceptibility)
• Health status and pre-existing pathology
• asthmatics, heart patients
• Concurrent exposures to organs (dust, CO, low 02)
• Limited human data and uncertainty in applying
  animal data to human response
• Small exposure range from no-effect to acute
  toxicity with uncertainty in epidemiological
  exposure levels

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Hydrogen Sulfide Hazard Assessment

• Emergency Actions
• Explosive 4.3 to 46, Heavier than air
  evacuate and remove ignition sources, ventilate,
  water spray
• Respiratory Hazard Use approved SCBA to rescue
  victims, if breathing apply 02, if not apply CPR,
  seek medical attention immediately, keep warm and
  calm, test atmosphere for toxic concentrations
• Eye Irritant irrigate eyes with water if
  irritated

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Hydrogen Sulfide Hazard Assessment

• Consensus Levels
• MSHA TLV 10 ppm, Ventilation plan actions
• 20 ppm for 15 minutes, allowable excursion
• OSHA 20 ppm (C), 50 ppm _at_ 10 min. peak / 1/shift
• ACGIH 10 ppm TLV-TWA, 15 STEL (NIC 1/5 ppm)
• NIOSH IDLH 100 ppm (Imminent Danger)
• AIHA ERPG3 100 ppm (60 min.) (life threatening)
• ERPG2 30 ppm (60 min.) (serious /
  irreversible)

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Hydrogen Sulfide Hazard Assessment

• Summary
• Acute Risk Moderate to high respiratory
  failure, cardiac and neurological damage, ocular
  irritation
• Small range of significant effects many will
  tolerate 50 ppm some fatalities, many injuries
  at 500 ppm
• Odor not dependable to detect use meters,
  detectors
• Use air supplied respirators for rescue Provide
  O2 / CPR
• Explosive, may collect in low areas
• Exposure concentrations may change without
  warning when low ventilation rates exist
• Stay out Stay alive