The Atomic Bombing of Hiroshima

On August 6, 1945, an American B-29 bomber named the Enola Gay left the island of Tinian for Hiroshima, Japan. This mission was piloted by Colonel Paul Tibbets. Hiroshima was chosen as the primary target since it had remained largely untouched by bombing raids and the bomb’s effects could be clearly measured.

The uranium 235 gun-type bomb, named Little Boy, exploded at 8:16 a.m. In an instant 80,000 to 140,000 people were killed and 100,000 more were seriously injured. The bomb exploded 1,900 feet above the center of the city, some 70 yards southeast of the Industrial Promotion Hall (now known as the Atomic Bomb Dome). The bomb had an explosive yield of about 12.5 kilotons of TNT.

In less than one second, the fireball had expanded to 900 feet. The blast wave shattered windows for a distance of ten miles and was felt as far away as 37 miles. Over two-thirds of Hiroshima's buildings were demolished. The hundreds of fires, ignited by the thermal pulse, combined to produce a firestorm that incinerated everything within miles of ground zero. Hiroshima had disappeared under a thick, churning foam of flames and smoke. The co-pilot, Captain Robert Lewis, commented, "My God, what have we done? "

About 30 minutes after the explosion, a heavy rain began falling in areas to the northwest of the city. This ‘black rain’ was full of dirt, dust, soot and highly radioactive particles that were sucked up into the air at the time of the explosion and during the fire. It caused contamination even in the remote areas from the explosion.

The survivors, who became known as hibakusha, sought relief from their injuries. However, 90% of all medical personnel were killed or disabled, and the remaining medical supplies quickly ran out. Many survivors began to notice the effects of exposure to the bomb’s radiation. Their symptoms ranged from nausea, bleeding, and loss of hair, to death. Survivors caught in the open within 1.2 miles of ground zero died within 6 weeks of radiation sickness.