Hydrogen Sulfide Hazard Assessment

1. Hydrogen Sulfide Hazard Assessment Erik Vermulen MSHA, District 9 Coal Safety and Health 303-231-5586 District 9 Coal Health

2. Hydrogen Sulfide Hazard Assessment Introduction • Occurrence in Mines, Scenarios • Detection • Range of Health Effects • Emergency Actions • Action Levels District 9 Coal Health

3. 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 District 9 Coal Health

4. Hydrogen Sulfide Hazard Assessment Detection • Odor: <0.02 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 District 9 Coal Health

5. 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 >1000 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 District 9 Coal Health

6. 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 miner’s locations, general duties, variance from normal • Fill out MSHA 2000-187 (MSHA 2000-194 if analysis needed) District 9 Coal Health

7. 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 manufacturer’s software, save files • Evaluated “STEL” file to see if any 15 minute increment > 20PPM • Evaluate TLV file to see if 8 hour >10 PPM • Contact District for assistance in writing the Citation, if applicable (Note: Instruments not listed by NIOSH or OSHA as standard method – rationale important) District 9 Coal Health

8. 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 District 9 Coal Health

9. 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 District 9 Coal Health

10. 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 @ 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) District 9 Coal Health

11. 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 District 9 Coal Health