Chlorine Gas-dispersion Range and Toxicological Effects: Release-volume and Seasonal Scenario-based Analyses

In this study, we aimed to analyze the dispersion characteristics of potential chlorine leakage incidents at the Yeosu Industrial Complex with a focus on seasonal meteorological conditions and variations in the release volume. To understand how damage patterns vary by season even under identical leakage conditions, summer and winter were selected as representative scenarios wherein temperature, atmospheric stability, and wind-speed differ markedly. The Areal Locations of Hazardous Atmospheres program was used for the dispersion analysis, which employed the average meteorological data from the preceding 10 years (2013-2022) and chlorine storage quantities specified by the Industrial Safety and Health Act as the basis for 50%, 100%, and 150% leak conditions. The Acute Exposure Guideline Level (AEGL) criteria were employed to calculate the impact range by concentration level, and the indoor and outdoor exposure times were compared. The simulation results indicated that during the winter months, stable atmospheric conditions and low temperatures resulted in the widest dispersion range; during the summer months, high-concentration zones formed near the leakage point, and the overall dispersion distance was relatively limited. Outdoor concentrations attained the AEGL-2 standard within minutes whereas, in indoor environments, even at equivalent distances, the time to reach the standard was delayed by tens of minutes, and thereby confirmed an initial exposure-mitigation effect. By quantitatively quantifying temporal and spatial variations in the exposure risk through an integrated consideration of seasonal weather conditions and indoor/outdoor environments, this study improves upon previous process safety management-based assessments that are centered on fixed worst-case scenarios.