Battery storage fire and explosion injures four firefighters at Japanese solar site

A fire broke out at a lithium-ion battery energy storage system co-located with the Takayanagi Solar Power Plant, Unit 6, operated by Hayashi Energy System in Isa City, Kagoshima, Japan. Neighbours reported white smoke coming from the site. Firefighters could not use water on the fire because of the risk of short circuit and electric shock from the battery equipment. After checking the temperature of the building, firefighters opened the door and found it filled with smoke. When they attempted to operate the building's smoke exhaust system, an explosion occurred, injuring four firefighters, one of whom sustained severe burns to the face and hands. The fire did not spread to the solar panels but the storage building was scorched and deformed. The fire was confirmed extinguished more than 20 hours after ignition, around 14:30 the following day.

Water could not be used to fight the fire due to the risk of short circuit and electric shock from the lithium-ion battery equipment, prolonging the incident. An explosion occurred when firefighters attempted to activate the building's smoke exhaust system after opening the door, suggesting a build-up of flammable or explosive gases inside the enclosed structure prior to ventilation.

1. Emergency responders should be aware that opening enclosures or activating ventilation and smoke exhaust systems on a lithium-ion BESS fire can trigger an explosion if flammable gases have accumulated, and should follow BESS-specific protocols rather than standard structure fire procedures.
2. Water should not be applied to lithium-ion battery fires because of the risk of short circuit, electric shock, or explosion, requiring alternative suppression or containment strategies and adequate firefighter training.
3. Operators and manufacturers should provide clear site-specific emergency response guidance to local fire services in advance, including gas venting behaviour and safe access procedures, to reduce risk to first responders.

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