OSAKA—Visitors stranded in the sweltering heat at the Osaka Kansai Expo venue lashed out at organizers, saying they failed to provide adequate information or direction during the ordeal.

A power outage halted services on Osaka Metro Co.’s Chuo Line, the only rail link to the expo site, on the night of Aug. 13, temporarily stranding about 30,000 people at the venue, according to the Japan Association for the 2025 World Exposition.

Many visitors spent the night at the expo site, but the exact number remains unknown because some returned home using partially restored service on the Chuo Line or by taking taxis.

“Many people went through a difficult experience, and we feel deeply sorry about that,” Jun Takashina, deputy secretary-general of the association, said on Aug. 14.

After the Chuo Line was suspended, 36 people who complained of headaches and other symptoms were transported by ambulance from both inside and outside the venue.

By 6:55 a.m. on Aug. 14, all visitors had left the venue. The expo opened at 10 a.m., one hour later than usual.

Osaka Metro officials apologized at a news conference on Aug. 14, saying, “We deeply regret the inconvenience caused to visitors and related officials.”

According to Osaka Metro, a short circuit near a rail joint that supplies electricity to the trains shut down the entire service between Yumeshima and Nagata stations at 9:28 p.m. on Aug. 13. The power failure occurred between Cosmo Square and Osakako stations.

Yumeshima Station, in Osaka’s Konohana Ward, is the closest station to the expo’s East Gate.
Osaka Metro began a shuttle service between Yumeshima Station and Cosmo Square Station, one stop away, at 10:10 p.m. on Aug. 13.

Trains ran thoughout the night to allow visitors to transfer from Cosmo Square Station to Nishi-Umeda Station on Osaka Metro’s Yotsubashi Line via the New Tram (Nanko Port Town) Line.

Full services resumed on the Chuo Line at 5:25 a.m. on Aug. 14.

Announcements directed visitors to wait under the towering wooden Grand Ring. People were seen sitting and resting with children in their arms on benches under the Grand Ring.

But there was little information about where they could receive water, food or other necessities.

A man in his 50s from Saitama Prefecture, who was waiting for a taxi at the West Gate, said there was also no guidance for the crowds of people heading for Yumeshima Station.

“We were packed in like sardines,” he said, adding that it was so hot that some people collapsed.

“Visitors need more information,” he said. “There is no crisis management at all.”

A man in his 60s from Hyogo Prefecture came to the West Gate in hopes of catching a taxi or bus, but a security guard told him it would be morning before he got a ride even if he lined up now.

The man said he decided to sleep at the venue.

“I never imagined I would become stranded here,” he said. “There should have been more announcements.”

Leandes Rosbach, a 19-year-old university student visiting from Germany, was unsure whether he could make it back to his hotel near Shin-Osaka Station and was unable to cancel his reservation.

Rosbach, who is studying Japanese, said the announcements in Japanese were too fast to understand, and that only a few announcements were given in English.

A woman in her 70s from Tokyo said she was worried someone might collapse because small children and elderly people were stuck at the venue.

“The expo has been open for a while now, so why isn’t there a more flexible response, like distributing water and chairs or announcing when the train service might resume?” asked the visibly exhausted woman.

At the expo site, the Osaka Healthcare Pavilion decided to open its doors for the night, and people lined up to spend the night inside.

The German Pavilion handed out snacks, while the Netherlands Pavilion opened its entrance area.

Some restaurants within the venue allowed visitors to wait indoors in air-conditioned spaces.

With the Obon midsummer holiday period under way, about 165,000 people visited the expo on Aug. 12, and large crowds were also present on Aug. 13.

According to the Osaka Municipal Fire Department, 33 emergency calls were made by 1 a.m. on Aug. 14, all from around the expo site.

The calls were related to heatstroke and discomfort caused by overcrowding.

The expo association said some pavilions and commercial facilities will be unable to operate on Aug. 14 due to the operational disruption.

A similar problem occurred on the night of April 22, when about 4,000 expo visitors were stranded at Yumeshima Station.

Services were suspended on the entire Chuo Line for nearly an hour because of an accident at Osakako Station.