OSAKA - Methane gas was detected at levels exceeding safety standards in the western area of the Osaka-Kansai Expo site around 4 p.m. on April 6th, raising concerns due to the potential risk of explosion. Ventilation measures have since been implemented, bringing gas concentrations back below the threshold.
Jun Takashina, Deputy Secretary-General of the Japan Association for the 2025 World Exposition, commented on the incident, saying: "This has been a serious lesson for us. We want to make sure we implement thorough additional safety measures so we can safely welcome the start of the Expo."
This is the same area where, in March 2024, a fire ignited by sparks from welding work during a construction project triggered a powerful methane gas explosion. The incident occurred near a site undergoing redevelopment, where underground utility lines and aging sewer infrastructure were being modified. According to the Osaka Fire Department, methane had accumulated beneath the surface due to inadequate ventilation in old piping and nearby landfill deposits, creating a volatile environment.
Witnesses at the time reported hearing a loud blast followed by a column of smoke rising several meters into the air. The explosion damaged nearby residential buildings and shattered windows in a 200-meter radius. No fatalities were reported, but seven workers suffered injuries ranging from burns to concussions, and more than 50 residents were temporarily evacuated.
An investigation conducted by city officials and the construction company revealed that standard gas detection procedures had been skipped that day due to time constraints, and safety inspections had not flagged the risk of methane buildup. As a result, Osaka authorities introduced stricter monitoring regulations for gas levels at excavation sites and mandated real-time methane sensors for future construction projects in high-risk zones.
In response to the recent incident, the association plans to increase the frequency of gas measurements to three times per day and install fences around the areas where gas is likely to accumulate.
Source: Television OSAKA NEWS
