The explosion at Aeon Mall Kumamoto during the Kumamoto earthquake and the Fire Service Act

On July 28, 2026, an earthquake with a maximum seismic intensity of 7 was observed in Kumamoto Prefecture, and a large-scale explosion occurred at "AEON Mall Kumamoto" in Kashima Town, Kumamoto Prefecture.
This accident, which occurred approximately 80 minutes after the earthquake, resulted in a tragic situation with multiple casualties.

This article will analyze the recent accident from the perspective of the Fire Service Act and consider disaster prevention measures that commercial facilities and tenant businesses should implement in the future.

　Results of "evacuation drills" based on the Fire Service Act and unforeseen disaster situations

Commercial facilities are required by fire safety regulations to conduct evacuation drills twice a year.
It has been reported that fire and firefighting drills were regularly and thoroughly conducted at Aeon Mall Kumamoto.

In fact, at the time of the earthquake (around 4:27 p.m.), there were approximately 3000 customers and 1300 to 1500 employees inside the facility. However, after the shaking subsided, the evacuation of customers was completed in about 30 minutes, demonstrating an extremely high level of initial evacuation.
This can be attributed to the training conducted in accordance with fire safety regulations during peacetime.

However, the explosion occurred around 5:50 p.m., approximately 1 hour and 20 minutes after the earthquake.
At the time, some employees had returned to the building to transfer sales proceeds to the safe, as instructed by the tenant management company, and were caught in the explosion, leading to a tragic secondary disaster.

　Fire safety risks (gas buildup) lurking in the gaps of the Fire Service Act and related regulations.

It has been suggested that the cause of the explosion was likely LP gas (propane gas), which was being used for air conditioning and cooking in restaurants, leaking due to the earthquake's tremors and igniting.
The problem here lies in the "blind spots" between modern building structures and current regulations.
The current law has the following underlying problems:

• Fire Law:

The regulations primarily aim to prevent fires, establish evacuation systems, and manage hazardous materials. While they include provisions for fire compartments and smoke exhaust systems, they lack specific regulations regarding "automatic forced exhaust to prevent gas buildup" within highly airtight structures.

• Building Standards Law :

While there is a demand for structural safety in buildings, and the airtightness and fire resistance of exterior walls (such as ALC panels) have improved, the design to release internal pressure during an explosion (such as interlocking detonation valves) is optional.

• High Pressure Gas Safety Act :

While automatic gas shutoff (earthquake-sensitive shutoff valves) is mandated for earthquakes of magnitude 5 or higher, it is not possible to completely prevent the risk of leakage of "residual gas" remaining in the building's piping downstream of the shutoff valve.
In other words, the current situation is that there is no legally unified coordination between fire safety equipment and building structures to address the complex mechanism in which leaked gas accumulates inside airtight buildings and explodes when it comes into contact with an ignition source (such as an electrical spark) without being properly vented.

In other words, the current situation is that there is no legally unified coordination between fire safety equipment and building structures to address the complex mechanism in which leaked gas accumulates inside airtight buildings and explodes when it comes into contact with an ignition source (such as an electrical spark) without being properly vented.

　Future disaster prevention measures and safety management required of businesses

This accident highlights that in large commercial facilities with vast open spaces, initial evacuation alone is not enough to protect the lives of employees.
The following measures may be taken by facility managers and tenant businesses in the future:

1. Develop a disaster prevention BCP (Business Continuity Plan) that defines rules for "after evacuation."

In addition to evacuation immediately after an earthquake, it is necessary to clearly state in the employment regulations and BCP (Business Continuity Plan) that "employees will not return to the facility for any reason (such as collecting sales revenue or retrieving goods) until safety is completely confirmed," and to ensure that all employees are fully aware of this rule.

2. Review of fire safety plans and comprehensive disaster training to enhance disaster prevention capabilities.

In addition to conventional evacuation drills for individual "fires" or "earthquakes," it is important to incorporate scenarios that anticipate complex disasters, such as "gas leaks and explosions after an earthquake," into fire safety plans.

3. Voluntary disaster prevention and safety measures in terms of facilities

While it is essential to meet legally mandated standards (such as the installation of automatic shut-off devices), it is also necessary to consider voluntary safety measures that go beyond the legal framework, such as the introduction of automatic ventilation systems (interlocks) linked to gas leak alarms.

　Final thoughts

The accident at Aeon Mall Kumamoto has raised serious questions about disaster prevention in large urban buildings. The reality is that simply meeting the current standards of the Fire Service Act and Building Standards Act does not guarantee absolute safety.

Support Administrative Scrivener Corporation provides services to companies and corporations, including not only applications for various licenses and permits, but also support for developing effective BCPs (Business Continuity Plans) and risk management consulting regarding compliance with laws and regulations such as the Fire Service Act. Please feel free to contact us to discuss creating a system to protect the lives of your employees and customers.

　　　　　　Person in charge: Junpei Tsukamoto

Related services are here

[Free consultation and estimate available here (inquiry form)]