Police found that the fire at the National Information Resources Service in Daejeon, which paralyzed large-scale national computer networks, was a man-made disaster caused by worker negligence.
On the 25th, the Daejeon Metropolitan Police Agency's dedicated investigation team said the fire at the national information resources center occurred due to negligence by workers who proceeded without cutting power and without performing insulation work.
The fire was found to have occurred during work with the main power to the uninterruptible power supply (UPS) cut. However, it was revealed that the workers did the job without cutting power to the battery racks (bundles of modules) consolidated with the UPS.
The workers also reportedly did not take accident prevention measures such as wearing insulating clothing or insulating the tools they used. It was determined they did not properly understand the need to discharge the charged batteries before working.
A police official said, "A site manager from a private firm with experience in UPS-related work explained the work method in advance, including cutting power to the battery racks, and even gave a demonstration," and noted, "But the contractors who actually did the work were deployed without hearing this explanation."
The National Forensic Service conveyed its appraisal ruling out the possibility that the fire was caused by battery thermal runaway. In a reenactment test by Korea Conformity Laboratories (KCL), the patterns during thermal runaway and during the fire were clearly different.
However, they did not pinpoint the exact act or reason that triggered the fire.
Police have booked four related officials, including the head of the national information resources center, the Director in charge of the work, and the Head of Team, for negligence in supervision as responsible for the fire, as well as 10 people including a contractor's workers and a supervisor firm's employees, on charges of occupationally negligent arson, and the case is under investigation.
Police also confirmed that the two companies that won the bid for the battery transfer project did not actually participate in the work, and that three subcontracted firms led the construction, and booked a total of 10 people, including the company representatives and workers, on charges of violating the Electrical Construction Business Act.
Of these, one person also faces a charge of occupationally negligent arson, bringing the total number of suspects booked in connection with this case to 19.