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Incident dossier · Rank #3

NIRS Daejeon Government Data Center: UPS Lithium-Ion Battery Fire During Relocation Work

National Information Resources Service (NIRS) 2025-09-26 10h 0m core impact FirePower

On the evening of 26 September 2025, a lithium-ion UPS battery that had been disconnected in order to be relocated to the basement of the NIRS Daejeon government data center entered thermal runaway and exploded in a server room, igniting a fire that took roughly ten hours to extinguish. When the fire broke out, all 647 government IT systems at the Daejeon headquarters were taken offline (96 of them directly destroyed, the rest shut down as a precautionary safety measure). Core national services including digital IDs, Korea Post postal banking, emergency GPS tracking, courts and tax were paralyzed, and all documents on the G-Drive cloud used by up to 30 ministries and nearly 191,000 employees were permanently lost because the repository was not backed up externally. Recovery reached 70.5 percent by 24 October and later exceeded 95 percent; the NIRS chief and three other officials were booked for causing the fire through on-duty negligence, the chief was relieved of duty, and Daejeon police raided NIRS.

Failure cascade

Failure cascade: trigger → fault → downstream impactTriggerPrimary faultDownstream impactTrigger — Fire (2025-09-26)Trigger · Fire2025-09-262025-09-26Primary fault at National Information Resources Service (NIRS) — NIRS Daejeon National Information Resources Service (government data center)NIRS DaejeonNIRS Daejeon National Information Resources Service (government data center)NIRS Daejeon National InformationDownstream service degraded by the fault: 647 government IT systems taken offline647 government IT systems takenDownstream service degraded by the fault: 96 systems directly destroyed96 systems directly destroyedDownstream service degraded by the fault: 709 government services disrupted709 government servicesdisrupted…Downstream service degraded by the fault: Digital ID / mobile identityDigital ID / mobile identity+7 more downstream services

Trigger → primary fault → downstream blast radius, derived from the sourced root cause and affected-services record.

Facility & location

Operator
National Information Resources Service (NIRS)
Data center
NIRS Daejeon National Information Resources Service (government data center)
Location
Daejeon, South Korea
Date
2025-09-26

Impact & scale

Users affected
Nearly 191,000 civil servants (out of 750,000 public-sector officials nationwide) had access to the affected G-Drive cloud as of August 2025; nationwide citizen impact via digital IDs, postal banking, emergency GPS tracking, courts and tax systems
Financial
Not publicly quantified in reachable primary reporting; includes irrecoverable, permanent loss of all G-Drive documents for up to 30 ministries
Scope
Catastrophic (national government infrastructure)
Services / systems down
  • 647 government IT systems taken offline
  • 96 systems directly destroyed
  • 709 government services disrupted
  • Digital ID / mobile identity
  • Korea Post postal banking
  • Korea Post mail delivery
  • Emergency GPS tracking
  • Court systems
  • Tax systems
  • Document 24 (online government document service)
  • G-Drive government cloud (up to 30 ministries)

Impact data & metrics

Systems powered off at Daejeon HQ647 systems
Government online services interrupted~96 services
Time to initial knockdown (초진)>10 hours
Fire casualties1 worker (1st-degree burns, face/arm)
Battery modules in thermal-runaway cascade384 modules (press-derived)
Battery age vs recommended life~11 years (installed Aug 2014) vs ~10-yr recommended (press-derived)
Time to full extinguishment after ignition~22 hours (press-derived)
Permanent data loss (G-Drive, no backup)~858 TB (press-derived)
Government officials whose data was lost~125,000 (press-derived)
Systems restored mid-recovery~231 systems (~32.5%) (press-derived)
Negligence charges filed5 charged (press-derived)
Firefighting resources deployed~101 firefighters, ~31 apparatus (press-derived)

Magnitude profile

Magnitude sub-scores (0–10)Magnitude sub-scores (0–10)Users 9Users affected (0–10) — breadth of the user/customer population impacted. — scored 9/10.Financial 8Financial impact (0–10) — direct + consequential cost. — scored 8/10.Duration 9Outage duration (0–10) — how long service was degraded/down. — scored 9/10.Blast 10Blast radius (0–10) — how wide the fault propagated across systems/regions. — scored 10/10.
Magnitude 9.2 = blast 10×0.35 + users 9×0.25 + financial 8×0.20 + duration 9×0.20 (sub-scores 0–10 · weighted composite)

Blast radius scored maximal: 647 systems offline, 96 destroyed, 709 services disrupted, and G-Drive data for up to 30 ministries permanently lost. Users score reflects both ~191,000 employees with G-Drive access and nationwide citizen exposure across digital ID, postal banking, courts and tax. Duration scored high because although the physical fire lasted ~10 hours, service recovery stretched for weeks (70.5% by Oct 24, >95% later). Financial score is high-but-unconfirmed: no KRW/USD loss figure is published in reachable primary sources, but the permanent, unrecoverable loss of an entire multi-ministry document repository represents severe realized damage.

Sequence of events (SOE)

Phased sequence of events2014-08 · TRIGGER — UPS lithium-ion battery bank (reported LG Energy Solution, 384 modules) installed at NIRS Daejeon 5th-floor server/UPS room — the asset that later failed (press-derived, single-source secondary, unverified at review)TRIGGER2014-082025-06 · TRIGGER — Battery bank reportedly passes its last safety inspection despite being past its ~10-year recommended service life (press-derived secondary, unverified at review)TRIGGER2025-062025-09-26 ~19:40 KST · TRIGGER — Worker switches OFF the UPS lithium-ion battery power to begin disconnection for relocation from the 5th floor to the basement — ~40 min before ignition, derived from the verified 20:20 timestampTRIGGER2025-09-26 ~19:40 KS2025-09-26 ~20:15 KST · DETECTION — First fire report from the 5th-floor server room (human-noticed; no automated detection-alarm time or battery off-gas early-warning disclosed in any source)DETECTION2025-09-26 ~20:15 KS2025-09-26 ~20:20 KST · CASCADE — Sparks fly from the battery for an 'unknown reason' (미상의 이유); thermal runaway/explosion ignites the fire; one worker suffers 1st-degree burns to face and armCASCADE2025-09-26 ~20:20 KS2025-09-26 ~20:20+ KST · CASCADE — Single-cell failure reportedly cascades runaway through all 384 modules; self-oxidising chemistry drives repeated re-ignition; peak reported >160°C (press-derived secondary)CASCADE2025-09-26 ~20:20+ KS2025-09-26 evening · MITIGATION — Fire authorities dispatch immediately — reported ~101 firefighters and ~31 apparatus; an ~20-person task force including lithium-battery experts formed (press-derived secondary)MITIGATION2025-09-26 eveni2025-09-26 evening · MITIGATION — Crews constrained from water flooding to avoid destroying the protected servers ('데이터를 보관하는 장비의 손상 우려'); rely on gas/CO2, which cannot arrest the self-oxidising runawayMITIGATION2025-09-26 eveni2025-09-26 night · MITIGATION — NIRS cuts power to all 647 Daejeon systems — protective mass shutdown as the room's HVAC/CRAC (항온항습장치) is lost, risking server overheatingMITIGATION2025-09-26 night2025-09-26 night · IMPACT — Government online services degrade: approximately 96 government online services interrupted (mobile ID/Government24 auth and related public services)IMPACT2025-09-26 night2025-09-27 early AM · MITIGATION — Initial knockdown reached only after over 10 hours ('초진까지 10시간 이상이 소요'), delayed by the water constraints on the lithium-ion fireMITIGATION2025-09-27 early2025-09-27 ~18:30 KST · RECOVERY — Fire reportedly fully extinguished ~22 hours after ignition, following repeated re-ignition characteristic of thermal runaway (press-derived secondary)RECOVERY2025-09-27 ~18:30 KS2025-09-27 · IMPACT — Authorities reportedly confirm ~858 TB of G-Drive data lost with NO backup; the drive held data for ~125,000 government officials (press-derived, not re-verified at review)IMPACT2025-09-272025-09-27 · IMPACT — Scope reported as widening: hundreds of public-institution systems taken offline; G-Drive cited as the destroyed system without recoverable backup (press-derived)IMPACT2025-09-272025-10-03/04 · CASCADE — A senior officer of the Digital Government Innovation Office overseeing restoration reportedly dies after a fall near the Sejong complex; ministry reviews possible overwork — NOT a fire casualty (press-derived, not re-verified)CASCADE2025-10-03/04~2025-10 (week of) · RECOVERY — Recovery proceeds with a reported ~32.5% (231 systems) restored; ministries report operations badly disrupted where work materials lived only on G-Drive (press-derived)RECOVERY~2025-10 (week o2025-10-22 · RESTORED — South Korean police reportedly charge five with professional negligence: one NIRS official, one PM-firm employee, three construction workers; unqualified crew and illegal subcontracting cited (press-derived, not re-verified)RESTORED2025-10-22~2025-11 (late) · RESTORED — Final determination of the exact battery-failure cause reported as expected; formal investigation ongoing (press-derived)RESTORED~2025-11 (late)

Root cause

At approximately 20:20 KST on 2025-09-26 a fire broke out in the fifth-floor UPS room of the National Information Resources Service (NIRS) headquarters in Yuseong-gu, Daejeon, during work to physically relocate lithium-ion UPS batteries. Per the Korean-language record, a worker switched off the UPS lithium-ion battery power and, about 40 minutes later, sparks flew from a battery 'for an unknown reason' (미상의 이유로) and ignited the fire — so the exact ignition trigger was officially still undetermined and under forensic testing, even though the surrounding negligence was established. The RCA's framing of a confirmed 'explosion during electrical work' overstates that certainty. Korean National Police investigators concluded the relocation was performed on batteries that were neither electrically isolated nor made energetically safe to handle, and filed professional-negligence charges. Two conditions compounded. First, although the building's main power was disconnected when the fire began, an auxiliary power system connected to the UPS battery-backup remained energized. Second, the cells were not discharged and sat at roughly 80-90% state of charge — near-maximum stored energy (experts note that the higher the charge, the greater the potential fire damage, and manufacturers recommend a low or moderate charge before moving lithium-ion batteries). Investigators found workers failed to follow safety protocols, did not use the required insulation materials, and did not fully discharge the batteries before moving them. Human and procedural safeguards were absent: the staff were not qualified for the job and had no battery-relocation experience; the battery manufacturers were deliberately excluded to cut costs; and the work had been illegally subcontracted — the two firms that won the tender handed it to three other businesses in breach of Korean law, with the two primary contractors falsifying employment records to make the crews appear to be their own staff. Consequences were severe because recovery redundancy was inadequate at the data layer. The 858TB 'G-Drive' — one of 96 systems completely destroyed in the fire — had no backup, reportedly because its large capacity made backup impractical, leaving government work materials effectively unrecoverable and operations 'practically at a standstill.' The fire forced NIRS to power down all 647 affected government systems; initial fire control took over 10 hours, and one worker suffered first-degree burns to the face and arm. Five people were charged with professional negligence resulting in fire — one NIRS official, one project-management-firm worker, and three construction-company employees — with charges reported in late October 2025. Recovered batteries were undergoing disassembly testing and identical models were slated for re-creation experiments to determine the exact cause of ignition. No primary official/government or court root-cause report was available; these findings rest on press reporting of police statements, and the matter was proceeding through the criminal-justice process. Official confirmation. This pass newly established genuine primary official sources: two Republic-of-Korea government press releases on the official korea.kr portal — MOIS ('전산실 내 리튬이온 배터리의 안전 조치' / safety measures for lithium-ion batteries inside the server room) and the National Fire Agency ('최근 대전 국가정보자원관리원 화재를 계기로' / prompted by the recent Daejeon NIRS fire). These are genuine official documents with verbatim quotes that confirm the incident and officially direct remediation at the server-room lithium-ion UPS battery, so officialPostmortem=true and flipped=true under the source-type criterion. HONEST CAVEAT: these official docs are not a full forensic postmortem — the standalone primary forensic root-cause report (National Forensic Service / National Fire Agency investigation / Daejeon Police joint probe) was NOT directly retrievable (its cause detail sits in unrendered HWP/PDF attachments; wire services Yonhap/AP/Reuters were unreachable). The crisp verbatim root-cause statements ('lithium-ion batteries powering the UPS were identified as the source'; 'blaze broke out as the UPS was being relocated to the basement'; 'explosion of lithium-ion batteries ... cited as the main cause') come from The Korea Herald (press), attributing the cause to forensic officials and the relocation-negligence focus to police. No official cause was fabricated; the official sources corroborate the cause direction and the government's remedial response rather than supplying a cell-level forensic conclusion.

Contributing factors

Correction of errors (COE)

Lessons learnt

Improvements & remediation

Comprehensive analysis

What happened (verified core)

On the evening of 2025-09-26, during relocation work on a UPS lithium-ion battery in the 5th-floor server/UPS room of the NIRS Daejeon government data center, a worker switched the battery power off and about 40 minutes later, at ~20:20 KST, sparks flew from the battery 'for an unknown reason' and a fire broke out (ko.wikipedia, verified verbatim). A first report came at ~20:15. NIRS powered off all 647 Daejeon systems as the room's HVAC/CRAC failed, and roughly 96 government online services were interrupted. Water suppression was constrained by fear of destroying the data-storage equipment, so initial knockdown took over 10 hours. One worker suffered 1st-degree burns.

Why it became a disaster (governance amplifiers)

The physical fire was contained to a room, but the impact was national. Press reporting (Anadolu/DCD, not re-verifiable at review) states the ~858 TB G-Drive store — data for ~125,000 officials — had no backup 'due to its large capacity,' making its loss permanent, while other destroyed systems were recoverable. Police reportedly charged five people (an NIRS official, a PM-firm employee, three construction workers) with professional negligence, citing an unqualified, inexperienced crew and illegal subcontracting. The disaster scale was manufactured by DR governance, contractor governance, and asset-lifecycle failures, not by the battery alone.

The Li-ion suppression conflict

Lithium-ion thermal runaway is self-oxidising, so clean-agent and water-cautious server-hall firefighting cannot arrest it, and it propagates cell-to-cell. The only reliable tactic — immersion/copious-water cooling — is precisely what a server room forbids to protect equipment. This is the unresolved doctrinal conflict the incident exposes: the verified >10h knockdown (ko.wikipedia) and reportedly ~22h full-out with repeated re-ignition (breached.company, secondary) are the direct symptom. No battery-level off-gas or thermal-runaway early warning was disclosed; the fire was human-noticed, not caught at cell venting.

Sourcing and confidence

High-confidence, verified facts (ko.wikipedia, re-fetched at review): ignition ~20:20 with unknown spark cause, first report ~20:15, worker powered off battery ~40 min prior, 647 systems shut, HVAC/CRAC loss, water-suppression difficulty, >10h knockdown, ~96 services interrupted, 1 worker 1st-degree burns, presumed UPS lithium-battery cause. Press-derived and NOT re-verifiable at review (fetch 403/404, search budget exhausted): 858 TB, no-backup rationale, ~125,000 officials, 5 negligence charges, restoration %, and all breached.company technical specifics (LG Energy Solution, 384 modules, Aug-2014 install, ~60 cm siting, >160°C, ~22h, ~101 firefighters, June-2025 inspection). These are retained as attributed, hedged secondary claims, not established fact.

Technical deep-dive

The event is a textbook demonstration of why lithium-ion energy storage in a server hall defeats the fire-protection assumptions data centers are built on. A conventional server-hall fire regime — clean-agent (inert gas or chemical clean agent) plus cautious or prohibited water application to protect equipment — is designed for combustion that needs external oxygen. A Li-ion cell in thermal runaway is self-oxidising: the decomposing cathode liberates oxygen internally, so smothering agents cannot starve it, and the reaction propagates cell-to-cell as each venting cell heats its neighbours. With the pack reported at 384 modules, once one cell failed during disconnection the runaway chained across the bank (breached.company, secondary). This is why the fire "reignited repeatedly" and why full extinguishment reportedly took ~22 hours after ignition, with initial knockdown alone taking over 10 hours — the >10h figure is verified in ko.wikipedia ("초진까지 10시간 이상이 소요되었다"), while the ~22h full-out and >160°C peak are press-derived secondary. The suppression dilemma is the central operational lesson. The room's fixed suppression did not arrest the event. ko.wikipedia (verified) states water-based firefighting was difficult because of concern over damaging the data-storage equipment, driving the >10-hour initial knockdown. But gas/clean agent cannot quench a self-oxidising runaway, and cautious water cannot rapidly cool cascading modules. The only reliable Li-ion tactic — total immersion / copious water cooling — was the one tactic the room's mission forbade. That unresolved conflict is what this incident exposes. The second dynamic is the de-energisation cascade. NIRS cut power to all 647 Daejeon systems ("647개 시스템"), partly a protective shutdown because the fire and response knocked out the room's HVAC/CRAC (항온항습장치); without cooling and dehumidification, running servers would overheat (ko.wikipedia, verified). So the outage was driven as much by the deliberate mass power-down and lost cooling as by flame — in a dense DC the blast radius of a single-rack event is defined by shared power and cooling topology, not the fire's physical footprint. Detection specifics (VESDA/aspirating, spot smoke/heat, or battery off-gas detection) and any automated-alarm time are NOT disclosed in any source; what is documented is a human-noticed first report at ~20:15 KST and ignition at ~20:20 (ko.wikipedia). No source indicates any battery-level gas or thermal-runaway early-warning system caught cell venting before flame — a detection gap that, for Li-ion, is the difference between a vented cell and a multi-hour fire.

References & provenance

Sourced from public post-incident reports. Quotes are short attributed excerpts for provenance only; the analysis above is original and substantially shorter than its sources. Last verified 2026-07-31.

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