The safety of carbon dioxide fire extinguishing facilities is studied through a fundamental case analysis of leakage accidents in carbon dioxide fire extinguishing facilities. In Korea, since 2001, there have been 11 accidents caused by leaks from carbon dioxide fire extinguishing facilities, killing 9 people and injuring more than 60 others. Recently, three subcontractors inhaled CO₂ gas from a transportation passage outside a collection chamber, killing two of them and injuring the other. This incident brought social attention to the CO₂ fire extinguishing facility in the first basement of S Electronics. In this study, we analyze the cause of the accident (e.g., pressure and temperature changes in the carbon dioxide leakage process) using a one-dimensional transient model, the effects of oxygen and CO₂ concentration at the location of the incident, and that these results can be used as basic data to prevent suffocation disaster in carbon dioxide fire extinguishing facilities.