The Japan Association for the 2025 World Exposition (hereinafter referred to as “the Association”) will publish the results of gas concentration measurements during the construction of the venue on a regular basis. The results of gas concentration measurements for January to March 2025 have now been compiled.
In addition, following the implementation of the safety measures announced on 24 June, 2024, the Association has confirmed that the measurement values are below the standard values, ensuring visitor safety at the site.
The measurement results are summarised below:
* Note: The “standard value” is 1.5 vol% as stipulated in the Ordinance on Industrial Safety and Health. The lower explosion limit of methane gas is 5 vol%.
(Inside buildings)
・No methane gas levels above the standard value were detected inside buildings between January and mid-March. In addition, the installation of mechanical ventilation equipment and detectors for gas countermeasure work has been completed for buildings in the GW construction area.
(In underground pits for electrical and telecommunications equipment etc.)
・The number of locations where methane gas levels above the standard value were detected in the underground pits for outdoor electrical and communication equipment, etc., is as follows:
[Inside the Expo site]
In the GW construction area, levels above the standard value were detected at three locations in January (near the east toilets of the GW construction area, to the west of the commercial facilities, and to the northeast of the commercial facilities), zero locations in February, and zero locations in March.
Regarding the two locations where levels of 5 vol% or more were previously detected (GW01 (detected in March 2024), GW02 (detected in May 2024, December 2024, and January 2025)), natural ventilation is being continuously implemented and after replacing the underground pit covers with perforated covers to increase ventilation, no methane gas levels above the standard value have been detected.
In the PW construction area, no levels above the standard value were detected.
[Transportation terminals]
Levels above the standard value were detected at zero locations in January, two locations in February (one at Transportation Terminal 1, one at Transportation Terminal 2), and zero locations in March.
At the two locations where levels above the standard level were detected in February, the covers were replaced with metal grating covers which offer better ventilation. Since then, no methane gas levels above the standard have been detected.
Regarding carbon monoxide, which has been announced in the measurement results until now, a detailed investigation concluded that its detection was due to a phenomenon specific to the gas sensors in which it was detecting gases not subject to measurement, and that there is no carbon monoxide in concentrations that would cause harm to health based on the opinions of experts.
Regarding gas safety management throughout the Expo, gas concentration will be continuously measured throughout the Expo site under the guidance of experts, and with the cooperation of each facility manager and project implementer, ventilation and safety checks will be thoroughly carried out at each facility to ensure an environment in which visitors can feel safe.
Specific actions that will be taken are as follows:
・Each facility manager and project implementer will thoroughly ventilate, conduct gas measurements, and notify the Association of the detected concentration.
・The Association will conduct gas measurements throughout the Expo site.
・The status of safety checks will be announced daily on the Association’s website and the Expo’s official app EXPO 2025 Visitors.
・A system will be established for constant close communication between facility managers and the Association regarding the status of gas concentration measurements and ventilation, etc.
・Online training sessions and on-site measurement simulations will be held for facility managers on how to measure and record gas concentrations and how to respond in the event of changes in gas concentrations.
