Documented Cases of Hydrogen Sulfide Poisoning

Extracted from the Occupational Safety and Health Administration (OSHA) Database October 10, 2024: US Chemical Safety and Hazard Investigation Board (CSB) Update Report dated March 2025 (OSHA Report still pending as of this writing) (2 Fatalities, 13 Evaluations at the hospital (local media reported 35 injured), broad areas of Deer Park and Pasadena, TX requested to shelter in place).On October 10, 2024, at 4:23 p.m., approximately 27,000 pounds of hydrogen sulfide gas were released during a maintenance activity at the PEMEX Deer Park Refinery in Deer Park, Texas.The release fatally injured two contract workers.Officials in the neighboring cities of Deer Park and Pasadena issued shelterin-place orders that lasted several hours.The contract pipefitters opened a flange on Unit AR-7 instead of Unit AR-6 which had been depressured and prepared for maintenance (the wrong unit).The flange that was opened contained hydrogen sulfide at 90% (900,000 ppm) while operating at normal flow and pressure. May 29, 2024, OSHA Database (1 Fatality, 3 Injuries) (Attempted Rescue)At 3:22 p.m. on May 29, 2024, Employee #1 was attempting to rescue a fellow employee who had been overcome by hydrogen sulfide (H 2 S) gas in an underground pump house.Prior to this incident, multiple coworkers had been working Appendix 2 Documented Cases of Hydrogen Sulfide Poisoning 30 Years of Data 1993-2023/30 Years of Tragedy Hydrogen Sulfide (H 2 S) Hazards: Risk Recognition and Prevention, First Edition.M. Darryl Yoes.