Survey: Only One Hiroshima Atomic Bomb Survivor Who Was Within 500 Meters of Hypocenter Remains Alive

The Yomiuri Shimbun

16:55 JST, July 30, 2025

Among the close-range hibakusha atomic bomb survivors who were within 500 meters of the hypocenter of the atomic bomb in Hiroshima, only one person remains alive today, according to a half-century-long survey conducted by Hiroshima University.

Tsunehiro Tomoda, 89, of Kadoma, Osaka Prefecture is the only proximal atomic bomb survivor who is still alive. The mortality rate of someone who was within half a kilometer of the hypocenter is said to be nearly 100%.

The survey targeted 78 people, but as of September last year, 77 had died.

The Hiroshima University Research Institute for Radiation Biology and Medicine and the city of Hiroshima, along with other organizations, conducted door-to-door interviews in the late 1960s to reconstruct the streetscape within a 500-meter radius of the hypocenter into a map. They confirmed the survival of 78 people.

Of the 78 individuals, 49 were male and 29 were female, with ages at the time of exposure ranging from 5 months to 54 years old. Most were indoors in reinforced concrete buildings or underground, where t the intense heat rays, blast waves, and radiation were blocked to some extent.

Since 1972, the institute has been conducting ongoing research into the physical and mental effects of the bombing and its impact on family formation through health checkups every two years. The incidence rate of cancer among the 78 survivors was 79% for the 29 who were exposed before the age of 20, 42% for the 31 aged 20 to under 40, and 6% for the 18 aged 40 or older, clearly showing that the younger the age at exposure, the higher the incidence rate.