The initial cause of the fire at the Coupang fulfillment center in Incheon in July of this year has been estimated to be thermal runaway of lithium-ion batteries built into stored goods, according to investigation results.

The National Fire Agency's Central Joint Fire Investigation Team pinpointed the product storage shelves on the 6th floor of Building B as the origin of the fire, based on a comprehensive analysis of statements from officials and CCTV footage.

Household goods containing built-in lithium-ion batteries were stored at the location.

The fire initially broke out and spread to product cases, packaging materials, and surrounding cardboard boxes before expanding along the upper floors and outer walls, according to the investigation.

Vertically, the flames spread to the 7th floor and the cafeteria on the 8th floor rooftop; horizontally, they expanded along the exterior wall of Building B toward Building B's neighboring areas.

During the fire, firefighting authorities established defensive lines around the entry ramp section, blocking the flames from spreading to Building A and the lower floors of the 5th floor and below.

Based on the investigation results, the National Fire Agency plans to overhaul response procedures for fires at large logistics warehouses and push for improvements in safety standards for storing lithium-ion batteries.

Considering the fire risks associated with battery charge levels, the agency also plans to consult with relevant ministries on measures to limit the charge state to a certain level or below when storing items in warehouses.

Earlier, when a fire broke out at the Incheon Coupang fulfillment center on July 18, a total of 917 firefighting and police personnel—including 507 firefighters and 371 police officers—along with 255 pieces of equipment including 7 helicopters, were deployed. The fire was completely extinguished at 8:35 PM on the 22nd, about 109 hours and 30 minutes later.

During the process, two firefighters sustained minor injuries due to smoke inhalation and exhaustion. Property damage was tallied at 37.4 billion won for real estate and 76.6 billion won for movable property, totaling 114 billion won.

Reported by Son Hyeong-an | Video by Kim Min-ji | Graphics by Yang Hae-min | Produced by SBS Digital News