Daejeon: Last month's deadly explosion at a Hanwha Aerospace facility in Daejeon appears to have occurred while cleaning a washing machine that may have contained explosive waste residue, police officials said Thursday. The incident, which took place on June 1, resulted in the deaths of five workers and injuries to two others, in the city located approximately 130 kilometers south of Seoul.

According to Yonhap News Agency, the Daejeon Metropolitan Police Agency unveiled its initial assessment during a press briefing. They cited a statement from a worker cleaning a tank within the washing machine at the time of the explosion. "I was cleaning a tank inside a washing machine at the time of the explosion. The blast seemed to originate from the machine," the worker reportedly told police.

The police revealed that workers used chisel-like metallic scalers to remove waste residue from the washing machine, which may have included explosive waste. In their investigation, police have secured 17 items from the scene, including tools believed to be used for cleaning the machine, and have requested a forensic analysis by the National Forensic Service.

Despite this initial assessment, police emphasized that the suspected cause of the explosion remains a possibility, and they are also considering other potential causes. These include electricity, impact, or friction within the workplace. Investigators have conducted three joint forensic examinations, seized and analyzed over 5,700 documents and items, and questioned 32 individuals involved in the incident.

Authorities have taken legal action against Ga Jae-woong, head of the Daejeon plant, and Sohn Jae-il, the CEO of Hanwha Aerospace, for their alleged responsibilities in the explosion.