Two workers died and three others were injured Tuesday while installing steel beams on the seventh floor of a building being constructed near JR Tokyo Station, police and other sources said.
The five male workers, believed to have been working on a 15-ton beam being carried by crane, fell about 20 meters to the structure's third floor after the beam came loose as they were installing it, the police said. The 33- and 43-year-old workers died under the beam.
One of the three who were injured had been in serious condition but regained consciousness, the police said. The two others suffered injuries and were taken to the hospital, but their conditions were not life-threatening.
The police suspect professional negligence resulting in injury and death.
Construction operator Obayashi Corp. said a total of five beams fell in the incident. Each beam is 13 to 18 meters long with a total weight of about 48 tons.
The construction site is located in a business district about 350 meters southeast of JR Tokyo Station.
A joint venture of Obayashi and Taisei Corp. has been building a 51-floor building with shops, medical facilities and a bus terminal, among others, at the site, according to the land ministry and other sources.
People near the site when the incident occurred said they heard a thunderous noise and felt earthquake-like shocks.
There have been several fatal accidents at construction sites in Japan in recent years, including one involving a bridge girder falling from a raised platform in Shizuoka, central Japan, in July, which left two people dead and six others injured.