This study conducted to analyze and compare the epidemiological and clinical characteristics of hydrogen fluoride exposed patients based on major burn criteria for the appropriate emergency department (ED) response to a mass casualty chemical spill. This retrospective cross-sectional study included the records of patients (n = 199) who visited the ED of Gumi City University Hospital from September 27, 2012, to October 20, 2012. Subjects were included in the major burn group (MBG) if they presented with wounds that required referral to a burn center according to the American Burn Association guidelines or in the non-major burn group (NMBG) if not. Males were predominant in both the MBG (n = 55, 48 males) and NMBG (n = 144, 84 males; p < 0.05). The most prevalent timeline for visiting the ED was the phase which included 9-32 hours post-leak of HF, including 45 patients (81.8%) in the MBG and 122 patients (84.7%) in the NMBG (p < 0.001). The respiratory tract was the site of greatest damage in patients in both the MBG and NMBG (n=47, 85.5% versus n=142, 98.6%, p < 0.001). Regarding dispositions, all patients in the NMBG were discharged (n=144, 100%); however, 8 patients (14.5%) in the MBG underwent other dispositions (discharge againt medical advice, 5 patients; admission, 1; death, 2, p < 0.05). Patient outcomes after major chemical contamination events should be characterized in future studies to maximize the quality of patient care.