Hiroshima: The Medical Fallout

Brandon Sugarman
February 21, 2019

Submitted as coursework for PH241, Stanford University, Winter 2018


Fig. 1: Severe burn marks of a female victim after the bombing at Hiroshima. (Source: Wikimedia Commons

On August 6th, 1945, a B-29 United States Bomber aircraft named Enola Gay flew over the Japanese city of Hiroshima and dropped the infamous Little-Boy atomic bomb from an altitude of 31,000 feet. [1] Fourty-four seconds after it was dropped, nuclear fission commenced and a single neutron initiated a supercritical reaction which increased the internal temperature of Little Boy to several million degrees hotter than the surface of the sun. [2] Absolute devastation ensued, as roughly 62,000 of Hiroshima's 90,000 buildings were demolished by the intense wind and firestorm generated by the powerful explosion.

Immediate Outcomes

Instantaneously, roughly 80,000 of Hiroshimas 290,000 citizens were killed, with an approximate 35,000 additional civilians wounded. [3] I will analyze the immediate medical consequences of the Little Boy explosion on the population of Hiroshima. Fig. 1 shows a female burn victim in the aftermath of the Hiroshima bombing, and illustrates the severe impact of high exposure to nuclear radiation on human skin. [4] Human exposure to radiation is most commonly quantified in Grays (Gy), with a lethal dosage generally falling somewhere close to 3 Gy. Many near the center of the blast radius were exposed to an excess of 1000 mGy (> 1 gray), and in most cases these targets suffered lethal burns or death by acute radiation sickness.

Gradual Outcomes

Perhaps the most troubling outcome of Hiroshima lay in the non-lethal pockets of the blast radius. In a study of 308,297 radiation-monitored workers in France, the UK, and the USA, research found that those exposed to 1000 mGy of radiation over the course of 27 years were over three times as likely to develop Leukemia than an average human being. [5] Certainly, the victims of Hiroshima exposed to a similar level of radiation over a shorter timespan suffered a similar fate. Additionally, in a study conducted by Yoshimoto, it was concluded that children born to mothers who had been exposed to over 0.3Gy of ionizing radiation had a statistically significant increase in risk of cancer. [6]

© Brandon Sugarman. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] G. F. Gosling, "The Manhattan Project: Making the Atomic Bomb," U.S. Department of Energy, DOE/MA-0002, January 2010.

[2] J. Xu, "The Atomic Bomb," Physics 241, Stanford University, Winter 2016.

[3] K. Palma, "Hiroshima: Urban Development Post Impact," Physics 241, Stanford University, Winter 2016.

[4] E. B. Douple et al., "Long-Term Radiation-Related Health Effects in a Unique Human Population: Lessons Learned from the Atomic Bomb Survivors of Hiroshima and Nagasaki," Disaster Med. Public Health Prep. 5, Suppl. 1, S122 (2011).

[5] K. Leuraud, et al., "Ionising Radiation and Risk of Death From Leukaemia and Lymphoma in Radiation-Monitored Workers (INWORKS): An International Cohort Study," Lancet Haematol. 2, e276 (2015).

[6] S. Yapa, "Effects on Children Exposed to Atomic Bomb Radiation Through Their Parents", Physics 241, Stanford University, Winter 2013.