The explosion at the Hanwha Aerospace Daejeon plant that killed or injured a total of seven people occurred in an instant without any sign, an investigation found.
According to the accident investigation report submitted by the National Fire Agency to Democratic Party of Korea lawmaker Park Jeong-hyeon's office on the 24th, a captured image from an external closed-circuit (CC)TV at Building 56's washing facility inside the Hanwha Aerospace business sites in Oesam-dong, Yuseong District, Daejeon, where the incident occurred on the 1st, was released.
The footage shows a massive flash and flames shooting out to the exterior of the building in an instant. Fire authorities said that their analysis of the video indicated a powerful explosion occurred immediately and then developed into a fire, without typical warning signs such as smoke rising first or a small fire breaking out.
At around 10:59 a.m. on the 1st, Building 56, where the disaster took place, was a cleaning-only facility used to wipe off residues stuck to tools and equipment used in the production process of propellant, the power source of rockets and missiles. Authorities identified "Separation wash room 1," located in the center of the building, as the point of origin. There, workers scraped the inside of equipment with paddle-shaped tools, soaked it in a tank for the first wash, and finished the process with a high-pressure washing device.
The National Fire Agency determined that residual propellant exploded for some reason, but the specific ignition cause has not yet been clearly identified. However, regarding the possibility that the detergent used in the process was a hazardous substance, component analyses requested from the National Fire Research Institute and the Korea Fire Institute (KFI) officially confirmed that both were nonhazardous substances.
The bigger problem is that the facility was left in a safety blind spot. Mixed explosives are classified as military goods under the Defense Acquisition Program Administration Act, so they fall outside the surveillance governed by the Dangerous Goods Safety Control Act enforced by fire authorities. Moreover, even the Defense Acquisition Program Administration, which holds licensing and oversight authority for military explosive products, treated Building 56 as a simple auxiliary washroom and excluded it from its management scope. Official permits from the competent authorities were limited to core facilities that directly manufacture and store explosives, and regular safety inspections were conducted only within the designated areas.