South Korean data center fire sparks a stark reminder

On September 26-27, 2025, South Korea’s National Information Resources Service (NIRS) data center in Daejeon (87 miles/140 km south of Seoul) suffered a catastrophic fire incident that started with a lithium-ion battery thermal event. The loss of the site crippled hundreds of government systems and exposed weaknesses in resiliency across systems and procedures.

The incident started as batteries were being relocated from the server floor of the data center to the basement. Contractors were removing aging Li-ion batteries, using a type of nickel‑manganese‑cobalt (NMC) cell chemistry, from the IT floor as a precautionary move. However, one of the battery packs in the basement entered thermal runaway that resulted in an uncontrolled fire. The fire burned for almost a day, taking more than 200 firefighters and 60 fire engines to contain and extinguish it.