H₂S Training Lessons From the Catalyst Refiners Tragedy

H₂S training remains the difference between a close call and a fatality. Hydrogen sulfide (H₂S) is one of the most dangerous atmospheric hazards in modern industry. It appears across refining, chemical manufacturing, wastewater treatment, agriculture, and waste management. Exposures above 100 ppm are considered immediately dangerous to life and health (NOAA, n.d.; OSHA, n.d.).

Despite decades of regulation and better detection technology, workers keep dying from H₂S exposure. Investigation reports repeatedly reveal failures in hazard recognition, procedural compliance, and emergency preparedness. Technology alone cannot prevent these incidents. Organizations still need competent workers, strong leadership, and H₂S training .

H₂S incidents often escalate into multiple-casualty events almost instantly. Workers can collapse before they escape or alert others nearby. Coworkers frequently attempt rescues without proper monitoring or protection, becoming victims themselves. These patterns appear again and again across CSB and OSHA investigations.

Many serious incidents occur during non-routine work, not normal operations. Shutdowns, turnarounds, and decommissioning activities often create unfamiliar hazards. The April 2026 release at Catalyst Refiners in West Virginia illustrates these risks clearly. It killed two workers, injured four others, and triggered a shelter-in-place order.

The Catalyst Refiners Incident

Catalyst Refiners specialized in reclaiming silver from spent catalyst materials in Institute, West Virginia. At the time of the incident, the facility was decommissioning operations and disposing of leftover chemicals. Notably, the company had no written procedure for disposing of these materials (CSB, 2026-a).

On April 22, workers combined a coagulant, a sodium trithiocarbonate solution, and diluted nitric acid in an open tank. A visible reaction produced a fog-like vapor cloud almost immediately. The operator shut off the flow and evacuated, but conditions deteriorated quickly.

Supervisors and additional workers who entered the area were overcome by the hazardous atmosphere. Surveillance footage showed multiple employees collapsing near the tank. Two workers ultimately died, and four suffered serious injuries as a result.

Emergency responders issued a one-mile shelter-in-place order for nearby residents. Twenty-two people underwent decontamination, and eighteen were transported for treatment (CSB, 2026-a). The event proves that serious hazards can persist even after production has stopped.

Immediate and Underlying Causes

The CSB’s preliminary findings point to several contributing failures. Most notably, no written procedure governed the chemical disposal process at all. Without documented steps, workers relied on verbal instructions, increasing the risk of error.

Chemical incompatibility also played a major role in the incident. Sodium trithiocarbonate reacts dangerously with strong acids like nitric acid. A proper hazard review should have caught this incompatibility before materials were combined.

Respiratory protection deficiencies compounded the danger further. Workers reported that respirator use was no longer required during decommissioning. Available respirators were fitted with particulate filters, offering no protection against H₂S gas.

Personal gas monitoring was also completely absent at the facility. Without real-time monitoring, workers had little warning before exposure became dangerous. This gap, paired with inadequate H₂S training, created conditions ripe for tragedy.

A Pattern Across Recent H₂S Incidents

Catalyst Refiners isn’t an isolated case. At PEMEX Deer Park in 2024, workers opened the wrong piping segment during maintenance. More than 27,000 pounds of H₂S escaped, killing two contractors and triggering a shelter-in-place order (CSB, 2026-b).

In 2025, six workers died at Prospect Ranch Dairy in Colorado from manure-related H₂S exposure. Initial victims collapsed, and rescuers without protection were then exposed themselves. OSHA proposed substantial penalties following the investigation (CBS News, 2026).

Production Waste Solutions saw a fatal exposure near a sump pit in Texas. Investigators cited failed training, missing hazard assessments, and inadequate controls (U.S. Department of Labor, 2023). Each case reflects gaps that better H₂S training could have closed.

A K&D Plumbing worker fell into a manhole with H₂S levels near 1,910 ppm. OSHA found no confined-space entry program existed at all. Penalties exceeded $184,000 for willful and serious violations (U.S. Department of Labor, 2024).

Contractor Management and H₂S Training Gaps

H₂S incidents create major challenges for contractor management. Contractors often perform maintenance and turnaround work where H₂S hazards may be present. When fatalities occur, investigators examine both the contractor and the host employer’s role.

Contractors frequently rely on host employers for facility-specific hazard information. When that communication fails, workers may enter dangerous conditions unknowingly. The PEMEX Deer Park incident shows how facility-level failures can cause contractor fatalities.

Decommissioning projects, like Catalyst Refiners, often shift risk profiles rapidly. Contractors may face new hazards without updated hazard communication or H₂S training. Both host employers and contractors share responsibility under OSHA’s multi-employer worksite policy.

Legal consequences following H₂S events often exceed regulatory penalties alone. Litigation frequently examines training documentation, competency verification, and hazard communication records (Kettlekamp & Junkin, 2025). Weak documentation in any of these areas increases legal exposure significantly.

Many organizations still rely on H₂S training like injury rates alone. These metrics say little about whether workers have real H₂S training. Leading indicators, including training standards and rescue readiness, matter far more.

The Case for ANSI Z390.1 H₂S Training

ANSI/ASSP Z390.1 offers one of the most comprehensive H₂S training frameworks available. It was built by industry stakeholders around competency, not simple attendance. Workers must demonstrate real understanding, not just sit through a class.

The standard also supports consistency across diverse, multi-employer workforces. It creates shared expectations for training content, response actions, and protective measures. This matters most on sites where multiple contractors work simultaneously.

ANSI Z390.1 strengthens emergency preparedness by emphasizing monitoring and rescue planning. Many fatalities happen because workers misjudge symptoms or attempt unsafe rescues. Strong H₂S training directly addresses this recurring, dangerous pattern.

For contractor management, the standard offers a defensible competency benchmark. It also carries legal value, since it reflects recognized industry practice. Adopting ANSI Z390.1 demonstrates real due diligence, not arbitrary internal requirements.

Conclusion

The Catalyst Refiners tragedy shows hydrogen sulfide remains an unforgiving hazard. Chemical incompatibility, missing monitoring, and weak procedures combined to cause fatalities. These same themes echo across PEMEX Deer Park, Prospect Ranch Dairy, and other cases.

Every incident examined here points to common organizational failures. Poor hazard recognition, insufficient monitoring, and inadequate H₂S training appear repeatedly. These aren’t unique technical problems; they’re recurring management gaps.

Contractor management remains central to preventing future H₂S tragedies. As reliance on contractors grows, so does the need for real oversight. Consequences extend beyond injuries into litigation, insurance costs, and reputational damage.

ANSI Z390.1 provides a practical, defensible path forward for organizations. It strengthens H₂S training while supporting broader contractor management and safety goals. The workers lost in these incidents deserve more than compliance on paper.

About the Author

James A. Junkin, MS, CSP, MSP, SMS, ASP, CSHO is the chief executive officer of Mariner-Gulf Consulting & Services, LLC and the chair of the Veriforce Strategic Advisory Board and the past chair of Professional Safety journal’s editorial review board. James is a member of the Advisory Board for the National Association of Safety Professionals (NASP). He is Columbia Southern University’s 2022 Safety Professional of the Year (Runner Up), a 2023 recipient of the National Association of Environmental Management’s (NAEM) 30 over 30 Award for excellence in the practice of occupational safety and health and sustainability, and the American Society of Safety Professionals (ASSP) 2024 Safety Professional of the Year for Training and Communications, and the recipient of the ASSP 2023-2024 Charles V. Culberson award. He is a much sought after master trainer, keynote speaker, podcaster of The Risk Matrix, and author of numerous articles concerning occupational safety and health. He is a proud veteran of the United States Navy and a strong advocate for veteran causes.

References

American National Standards Institute [ANSI]. (2024). ANSI/ASSP Z390.1-2017: Accepted practices for hydrogen sulfide (H₂S) training programs. American Society of Safety Professionals [ASSP]. https://my.assp.org/s/product-details?id=a1BUJ000004hFzD&_ga=2.248602946.45673660.1786710776-1574565536.1712673043

CBS News. (2026, February 24). Three companies cited for deaths of Northern Colorado dairy farm workers. https://www.cbsnews.com/colorado/news/three-companies-cited-deaths-northern-colorado-dairy-farm-workers/

National Oceanic and Atmospheric Administration. (n.d.). Hydrogen sulfide. https://cameochemicals.noaa.gov/chemical/3625

Occupational Safety and Health Administration. (n.d.). Hydrogen sulfide hazards. https://www.osha.gov/hydrogen-sulfide/hazards

U.S. Chemical Safety and Hazard Investigation Board. (2026-a, August). Fatal toxic hydrogen sulfide release at Catalyst Refiners, Inc., Institute, West Virginia: Investigation update. https://www.csb.gov/assets/1/6/final_investigation_update_catalyst_refiners_.pdf

U.S. Chemical Safety and Hazard Investigation Board. (2026-b, February 23). Final investigation report: PEMEX Deer Park hydrogen sulfide release. https://www.csb.gov/pemex-deer-park-chemical-release-/