# Assessing Crisis Management Tools for Sustainability of Industrial Safety
## 4 Model Situation
### Results of Models of Individual Scenarios
#### 4.1.2 Scenario 1.2. High-Concentration Ammonia Leak with Fatal Consequences  
The model for this scenario was constructed by simulating a high-concentration ammonia leak under stable atmospheric conditions, designed to emphasise a more extreme hazard situation than Scenario 1.1. This simulation considered atmospheric conditions (\(t=25\)\({}^{\circ}\)C, \(v=1\) m.s\({}^{-1}\)) and the geographic location (GPS: 49.135727, 20.433323). Ammonia's molecular weight (17.03 g.mol\({}^{-1}\)) and boiling point (\(-33\)\({}^{\circ}\)C) were also factored into the calculations. Using the ALOHA 5.4.7 software, danger zones were defined based on ERPG thresholds, with dispersion patterns modelled accordingly. Scenario 1.2 simulates an ammonia leak occurring under stable atmospheric conditions but with a significantly higher leakage rate compared to Scenario 1.1. While both scenarios were conducted under comparable atmospheric conditions, Scenario 1.2 models a considerably higher ammonia concentration due to the elevated release rate and restricted dispersion dynamics, resulting in more severe exposure risks. The concentration difference between these two scenarios can be attributed to the proximity of the leak source to enclosed areas, which restricts the dispersal of ammonia. As a result, higher concentrations accumulate near the leak source, creating more hazardous conditions. The ALOHA model identified three primary zones of risk, with a focus on life-threatening ammonia concentrations, as follows:  
* ERPG-1 zone (300 ppm \(\leq C(x,y,t)<\) 2160 ppm) presents a lower immediate risk compared to ERPG-2 and ERPG-3 but still carries significant health hazards if exposure is prolonged. Within this concentration range, individuals may experience respiratory discomfort and irritation, with the potential for long-term health effects if not evacuated in time. Although the urgency for evacuation is not as critical as in higher zones, protective measures must be implemented to prevent adverse health outcomes over extended periods of exposure. * ERPG-2 zone (2160 ppm \(\leq C(x,y,t)<\) 4300 ppm) covers an area where exposure lasting around 30 min can result in serious health issues, including respiratory tract damage, lung injury, and cardiovascular complications. Although the health risks in this zone are lower than in the ERPG-3 zone, the possibility of life-threatening consequences persists if timely intervention is not undertaken. Emergency response teams need to act swiftly to mitigate the dangers posed by this high concentration of ammonia. * ERPG-3 zone (\(C(x,y,t)\geq 4300\) ppm) poses an extreme and immediate threat. At this concentration level, exposure can lead to fatal health effects within minutes due to rapid and severe impacts on the respiratory system and other vital functions. The urgency for evacuation in this zone is heightened by the elevated concentration, which drastically reduces the available time for safe evacuation and intervention. Immediate and coordinated action is critical to prevent casualties. This scenario emphasises the necessity for rapid evacuation and timely intervention, as the higher concentration levels leave minimal room for error. In contrast to Scenario 1.1, where the risk zones were more widespread, the hazard in Scenario 1.2 is highly concentrated near the leak point, increasing the likelihood of life-threatening exposure within a relatively short distance. This difference further underscores the impact of environmental and physical conditions, such as the enclosed space, on the dispersion and accumulation of hazardous substances (Table 3).