Managing Hydrogen Sulfide Exposure Risks in Oil and Gas Operations: A Barrier-Based Review of Gas Detection, Respiratory Protection, Confined Space Entry, and Emergency Response

Hydrogen sulfide (H₂S) remains one of the most severe acute toxic gas hazards in oil and gas operations. Its occupational relevance is driven by a combination of high toxicity, rapid incapacitation potential, accumulation in low-lying and confined spaces, flammability, and the unreliability of odor as a warning mechanism. This structured narrative review synthesizes open regulatory, toxicological, incident-investigation, and peer-reviewed evidence to develop a barrier-based framework for managing H₂S exposure risks in drilling, production, maintenance, tank, waterflood, and confined-space operations. Sources were selected from official occupational safety agencies, toxicological guidance, formal incident investigations, recognized risk-management frameworks, and peer-reviewed literature with verified DOI or PubMed indexing where applicable. The evidence indicates that effective H₂S risk management cannot rely on personal protective equipment or exposure-limit compliance alone. Instead, it requires integration of source identification, engineering controls, fixed and personal gas detection, pre-entry and continuous atmospheric monitoring, ventilation, work authorization, respiratory protection for immediately dangerous to life or health conditions, rescue readiness, training, and management-system assurance. Incident evidence further shows that missing or weak barriers can expose not only workers but also co-workers, responders, and nearby non-employees. The review proposes a six-element framework linking hazard identification, source and engineering controls, detection and verification, work authorization, protection and emergency response, and assurance and learning. The framework is intended to support quality, health, safety and environment (QHSE) managers, safety engineers, supervisors, and emergency planners in developing auditable H₂S risk-control programs for high-risk oil and gas environments.