April 7, 2025

Methane gas with concentrations that could trigger an explosion was detected on April 6 at the Expo site in Osaka City (Osaka Pref.), where a 3-day “test run” rehearsal for the “Expo 2025 Osaka, Kansai” was being held in which a total of about 90,000 citizens participated.

Firefighters were dispatched to the site in a disaster response. However, no announcements were made to alert people at the venue, and the use of restrooms and food trucks continued.

Reportedly, the lowest concentration (5 vol%) or higher of gas that could spark an explosion was detected near the area where the explosion and fire occurred last March.

Japanese Communist Party member of the Moriguchi City Assembly (Osaka Pref.) Teramoto Kenta, a former firefighter, was at the site at that time.

He said, “Normally, a ‘fire cautionary area’ is supposed to be set immediately to prohibit the use of fire within such an area, but to me, both the local fire department and the Expo 2025 association seemed hesitant to establish a restricted zone even after the arrival of firefighters.”

Past related article:
> Flammable gas detected at Osaka Expo construction site [May 31, 2024]