ABSTRACT
Introduction: In recent decades, an increase in natural disasters has led to the Natech events occurrence, which are technological accidents triggered by natural hazards. This study aims to assess the risk of chemical release of the H2S toxic gas following an earthquake from the refinery. Method: The Natech risk assessment was carried out in potential earthquake risk scenarios via a semi-quantitative method using Rapid-N software. The reference scenario was obtained using the Australian SMUG Model, which has presented precise prioritization. Findings: The Natech risk assessment has shown 40 possible earthquake risk scenarios from 5 enclosing Faults in Tehran (North Tehran, Mosha, North Ray, South Ray, and Kahrizak) with an extension of more than 15 km. The earthquake moment magnitudes of 7.5, 7.1, 6.5, and 5.9 were obtained on the Richter scale and at two Focal depths of 5 and 10 km. The South-Ray Fault (HSR-1) was selected as the reference scenario with a moment magnitude of 7.5 on the Richter scale at a Focal depth of 5 km and a distance of 5.5 km from the earthquake epicenter. The highest probability of Natech risk has shown the release of H2S toxic gas in an area with a radius of 6.59 km from the studied vessel in atmospheric stability conditions. Conclusion: Legislation in line with risk reduction, planning for the transfer of potentially dangerous industries to outside urban areas, monitoring land use laws, and promoting coordination between the government, industries, and people in the management of risks caused by industries containing hazardous substances and processes, assessing the risk of Natech events and their consequences, strengthening risk communication and the installation of early warning systems, and public education to adopt personal and socially safe behaviors when facing natural disasters are recommended.
ABSTRACT
OBJECTIVE: To analyze the consequences of the Natech scenario of H2S toxic gas release from an oil refinery near Tehran and its effects on surrounding residential areas following an earthquake. METHODS: This research was an applied study. The Natech risk map and the end-point distance of gas release were determined using the Rapid-n software and the Worst-Case Scenario of RMP, respectively. RESULTS: Regarding the high seismic vulnerability of the structures affected by the Natech risk, all residents of this area were simultaneously affected by earthquake and the toxic gas inhalation. In comparison to earthquake, response capacities were poor for Natech events, due to insufficient resources, limited accessibility, lack of planning, and unsafe evacuation places in exposed regions. Unlike earthquake, few studies have been conducted on Natech risk assessment and related consequences in Iran. Our study not only covered this gap but also revealed some dimensions of consequences of human, structural, and response capacities. CONCLUSIONS: It is recommended to have plans for implementing short-term such as identifying vulnerable industries and areas, public awareness and long-term such as land use planning measures to reduce Natech risk and resilience improvement.
Subject(s)
Earthquakes , Humans , Iran , Oil and Gas Industry , Risk Assessment/methods , IndustryABSTRACT
BACKGROUND: In recent decades, earthquakes, as natural hazards that caused direct effects both on communities and the chemical industry, produced many Natech events. Natech term is utilizing to describe the technological disasters caused by natural hazards. This study was conducted on the emergency evacuation challenges of residential areas adjacent to a refinery near Tehran based on H2S toxic gas release following a possible earthquake scenario. METHODS: This Research was an applied study at two phases in 2020. In the first phase, a review study was conducted to identify the community's previous experiences on emergency evacuation following Natech events. In the second phase, the challenges of emergency evacuation were analyzed based on the scenario of a possible earthquake and gas release from the refinery. RESULTS: Due to the high seismic vulnerability of structures in the area affected Natech risk, the total Resident population in this area would be affected simultaneously by an earthquake and H2S gas release in concentration 30 ppm as the result of the earthquake impact on chemical facilities. Emergency evacuation would be inevitable. The existing evacuation places are very unsafe and dangerous due to having open spaces. The nearest suitable evacuation places were found in the north direction for more than 38 % of the exposed population and in the east, west, and south direction for more than 61% of them. CONCLUSIONS: The emergency evacuation challenges were discussed in 4 viewpoints, disrupted or interrupted rescue and firefighting operation, unnecessary evacuation, frequent evacuation, and evacuation behavior. The measures such as revising and updating emergency evacuation maps; public informing, training, preparedness; providing protocols and training for operational and therapeutic response teams; and coordination improvement can help resilience increasing to such disasters.
