OSAKA - An explosion and fire at the Osaka-Kansai Expo construction site in March has been detailed by a male worker who was near the scene. In early June, he provided his account to the Asahi Shimbun, along with photos showing damage not previously disclosed by the Japan Association for the 2025 World Exposition.
'Something exploded…'
'It sounded like a collision between cars at high speed or a giant balloon bursting.'
The explosion occurred on March 28 at a toilet facility under construction on the west side of the site. The worker was outside the building at the time.
The reporter confirmed the authenticity of the worker's photos and testimony through metadata and information known only to those involved in the construction.
'I didn't feel any shaking, nor was there fire, smoke, or any strange smell. When I went to see what happened, the welder was standing there dazed, saying "I don't know, but there was an explosion…" Others were also confused.'
The Expo Association believes that sparks from welding ignited methane gas accumulated in a space under the floor, causing the explosion.
The blast damaged about 100 square meters of the concrete floor and roofing materials, requiring repairs.
Cracked Concrete Floor, Warped Metal Cover
'Afterwards, people from the JV (Kashima-Tobishima Construction Joint Venture) overseeing the section gathered, took photos, made calls, and interviewed workers.'
'I left for work but returned a few hours later and took photos to report to my superiors and colleagues.'
The photos, taken with a smartphone, show cracks in the concrete floor near an emerald green aerial work platform used by the welder. Other images reveal warped metal covers and scattered concrete debris.
'The concrete floor is thick, so the explosion was quite powerful. The ventilation cover, usually open during work, was inexplicably closed. The red metal cover of the floor hole was blown off from below.'
The Expo Association provided a single photo to the media the day after the explosion, which didn't fully show the damage. The cracks in the worker's photos were not visible.
Worker Takes Action
On May 19, the Asahi Shimbun reported that the JV notified the fire department about four and a half hours after the explosion. The fire department confirmed roof damage.
On May 22, the Expo Association acknowledged roof damage, stating the JV had not reported it. Criticism of the Association's safety stance arose in the Diet and Osaka municipal assemblies.
'Around that time, I saw a video on social media of a Diet member urging a minister to release more photos of the damage. I thought it was inappropriate to only show one photo.'
'To help, I replied to the member's post with my photos. The post was widely shared after the member introduced it.'
The Expo Association then released three additional photos on May 27, revealing new damage but taken four to nineteen days after the explosion.
No Regrets About Sharing Photos
The worker, who has no strong stance for or against the Expo and works for a living, expressed frustration with the Association's handling of the incident.
'They show off things like the wooden ring roof to VIPs but try to hide inconvenient truths like this explosion. I think it's wrong to conceal the facts.'
His calm tone turned angry. Although sharing internal photos is forbidden, he has no regrets.
'The construction cost is 235 billion yen, mostly taxpayer money, affecting people struggling financially.'
'Unlikely to Meet Deadline'
Despite his dedication, the worker finds it hard to stay motivated.
'We have to demolish it in six months. Many feel the same. Building on land prone to subsidence is dangerous, but the Association thinks it's fine if it lasts six months.'
The Expo site is on reclaimed land, and Osaka City acknowledges the risk of subsidence.
'From my experience, the construction won't be 100% complete by the opening. Rushing might lead to accidents...'
Source: Asahi
