Abstract

The transportation of ammonia—a widely used industrial chemical—presents significant risks, including leaks, fires, and explosions. This study aimed to assess the risks of transporting ammonia in the southern part of Thailand and to create a detailed risk evaluation using geospatial methods. We used the Areal Locations of Hazardous Atmospheres (ALOHA) to comprehensively simulate five ammonia accident scenarios: toxic vapor cloud, flammable areas (flash fire and jet fire), boiling liquid expanding vapor explosion (BLEVE), and vapor cloud explosion while risk, severity, and evacuation routes were mapped using ArcGIS software. The simulation results reveal that variations in wind direction influence ammonia spread across different seasons. In summer and winter, the wind direction is northeast, and in the rainy season, it shifts to southwest. In scenario 1, the red zone extends 2,400 meters from the source, with ammonia levels reaching up to 505,000 ppm, while in scenario 2, the red zone spans 368 meters. Explosive hazards (BLEVE and VCE) have ranges of 207 and 310 meters, respectively. While our study provides detailed mapping of ammonia hazard zones, future studies are needed to incorporate socio-economic factors into geospatial analyses to improve evacuation strategies and risk mitigation. Consequently, the maps produced can be utilized as essential decision-making tools in emergency response planning and management, which may reduce the death toll during a disaster in the future.