Investigators launch joint probe of Hanwha Aerospace blast that killed 5, injured 2 — third major accident at same site

Police, fire authorities conduct joint on-site inspection Monday

Dedicated investigative teams formed to determine cause, liability

The Hanwha Aerospace factory in Yuseong-gu, Daejeon, where an explosion killed five workers and left two others seriously injured on Sunday. [Joint press pool/Yonhap]

Police and fire authorities launched a joint forensic inspection Monday at the Hanwha Aerospace factory in Daejeon, where an explosion killed five workers and injured two others — the third major blast at the same facility in less than a decade. Separate explosions at the site in 2018 and 2019 killed five and three workers, respectively. The repeated tragedies at a single location have prompted calls for a thorough investigation and a fundamental safety overhaul, while concerns have also emerged that the findings could affect the safety certification of the company's export products.

Police, fire authorities, the National Forensic Service and the Korea Occupational Safety and Health Agency began a detailed joint inspection of the accident scene at 10 a.m. Monday. The goal is to determine what triggered the explosion.

According to police and fire authorities, the blast and subsequent fire broke out at around 10:59 a.m. Sunday in the cleaning room of Building 56 at the Hanwha Aerospace factory in Oesamdong, Yuseong-gu, Daejeon. Hanwha said seven workers had been cleaning tools contaminated with propellant — an explosive compound — when the accident occurred.

About 20 minutes after the explosion, at around 11:17 a.m., fire authorities declared a Level 1 emergency response and deployed 33 pieces of equipment and 101 personnel to fight the blaze, which was brought under control roughly two hours later. Five workers died and two sustained serious injuries; one of the injured was reported to be suffering severe burns across the body.

Eom Hyo-sik, director of defense and security at the Korea Defense and Security Forum, worked at Hanwha during the 2018 and 2019 accidents. He said propellant is a sensitive material that can ignite from static electricity alone, but added that investigators should keep multiple possibilities open — including whether the explosion actually originated in the cleaning room or in an adjacent workspace.

The Daejeon Metropolitan Police Agency and the Daejeon District Prosecutors' Office each formed dedicated investigative teams to examine both the cause of the explosion and potential corporate negligence. The Ministry of Employment and Labor issued an immediate work-suspension order for the Hanwha Aerospace facility and opened an investigation into possible violations of the Occupational Safety and Health Act and the Serious Accidents Punishment Act.

Third disaster in 7 years puts factory safety record under scrutiny

The Daejeon factory has now seen three major explosions claim a combined 13 lives. In May 2018, two workers died at the scene and three more succumbed to burn injuries during treatment. In February 2019, an explosion and fire in the propellant demolding room of Building 70 killed three more workers.

Both earlier accidents were attributed to inadequate safety management. In the 2018 incident, investigators found that workers had struck a propellant container valve with a rubber mallet after the filling equipment malfunctioned. The 2019 explosion was caused by residual static electricity inside a rocket propellant unit igniting the explosive material; it later emerged that a grounding device to discharge static electricity had never been installed.

The Ministry of Employment and Labor conducted special labor inspections and safety audits following those accidents, but the recurrence of a fatal disaster seven years later is expected to put the factory's safety practices under intense scrutiny once again.

At a briefing Sunday, Hanwha said the cleaning room where the accident occurred had been classified as a low-risk area. The company said flame-retardant suits and blast barriers were installed in certain zones and that some areas were partially isolated, but added that the exact point of origin of the explosion required further confirmation.

Shin Jong-woo, secretary-general of the Korea Defense and Security Forum, said investigators must examine the site closely to determine whether safety protocols were strictly followed. "This is not a place that just started cleaning operations yesterday," he said, adding that a fire breaking out in the cleaning room was difficult to understand.

Kong Ha-seong, a professor of fire and disaster prevention at Woosuk University, said static electricity management is the cornerstone of safety in high-risk propellant processes, and that even a minute discharge can trigger a large explosion. He added that static electricity can build up in unexpected ways — including during high-pressure water use or from friction caused by work clothing.

Explosion raises concerns over Hanwha Aerospace exports

Concerns have emerged that the investigation's findings could affect future exports and deliveries. The Daejeon factory is understood to produce several weapons systems, including the Korea Tactical Surface-to-Surface Missile (KTSSM), the Chunmoo multiple rocket launcher, the long-range surface-to-air missile system L-SAM, and the air defense system Cheongung-II.

Eom said the accident could negatively affect the perceived reliability of export products depending on which system the propellant in question was destined for. "The cause of the accident must be thoroughly identified to dispel the anxiety of countries that import these weapons," he said.

The two major national labor federations each issued statements condemning the accident as a systemic failure of safety management and calling for severe punishment of those responsible and the introduction of concrete preventive measures.

The Korean Confederation of Trade Unions said officials indicted over the 2018 and 2019 explosions received suspended sentences, while Hanwha itself was fined only 50 million won ($33,100). "Perfunctory, slap-on-the-wrist punishment has once again led to a serious industrial disaster and cost workers their lives," the federation said.

The Federation of Korean Trade Unions also issued a statement saying that the recurrence of similar accidents at the same facility made a comprehensive review of the safety management system and disaster prevention framework unavoidable. It called on the government and the company to clearly establish the cause of the accident and fix responsibility.

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