Analyses have shown that detonating an atomic bomb in a modern city could kill as many as 1 million people.

The claim is that published analyses existed showing an atomic bomb detonated in a modern city could kill as many as 1 million people. TRUE: at least one credible published analysis available by October 2005 (e.g. government, academic, NGO or think-tank nuclear-effects study, such as OTA, Natural Resources Defense Council, Federation of American Scientists or similar city-attack casualty modelling) gives an upper-end fatality estimate of roughly 1 million or more for a single atomic/nuclear detonation in a major city. MOSTLY TRUE: such analyses exist but reach the ~1 million figure only under assumptions the claim does not state (e.g. a large thermonuclear rather than fission weapon, or including later radiation deaths), with the headline figure otherwise as stated. MIXED: published analyses of the period cluster substantially below 1 million for an atomic bomb, with only isolated outliers reaching that level. MOSTLY FALSE: published estimates for a single city detonation top out well below 1 million (e.g. in the low hundreds of thousands), so the claim inflates a real body of analysis. FALSE: evidence shows no such casualty analyses existed or that published analyses expressly rule out fatalities approaching 1 million.

Set before the research began.

1. E1 Nuclear bomb and public health PMC (Shan Xu and Alicia Dodt, Viewpoint) · 14 June 2023

   “According to their calculation, 470,000 of the population of 4.3 million would die, 630,000 would be injured.”

2. E2 Consequences of regional scale nuclear conflicts Atmospheric Chemistry and Physics Discussions (Toon, Turco, Robock et al.) · 22 November 2006

   “An individual in possession of one of the thousands of existing lightweight nuclear weapons could kill or injure a million people in a terrorist attack.”

3. E3 Long-Classified U.S. Estimates of Nuclear War Casualties During the Cold War Regularly Underestimated Deaths and Destruction National Security Archive, George Washington University (William Burr) · 14 July 2022

   “Once thermonuclear weapons became available during the 1950s, however, the prospects for levels of casualties in the hundreds of thousands and millions became certain.”

4. E4 Nuclear bomb and public health PMC (Springer Nature journal article, Xu and Dodt) · 14 June 2023

   “The Office of Technology Assessment (OTA) in the United States (U.S) depicted damage anticipated in Detroit, a select U.S city [39]. They assumed an evening attack with detonation at an altitude of 6000 feet, without warning, and with no other cities attacked. According to their calculation, 470,000 of the population of 4.3 million would die, 630,000 would be injured.”

5. E5 Long-Classified U.S. Estimates of Nuclear War Casualties During the Cold War Regularly Underestimated Deaths and Destruction National Security Archive, George Washington University · 14 July 2022

   “Once thermonuclear weapons became available during the 1950s, however, the prospects for levels of casualties in the hundreds of thousands and millions became certain.”

6. E6 Long-Classified U.S. Estimates of Nuclear War Casualties During the Cold War Regularly Underestimated Deaths and Destruction National Security Archive, George Washington University · 14 July 2022

   “While all of the estimates were conjectural, some admittedly were lowballs.”

7. E7 Effects of nuclear explosions - Wikipedia Wikipedia · 12 June 2003

   “Advanced computer modelling of real-world conditions and how they impact on the damage to modern urban areas has found that most scaling laws are too simplistic and tend to overestimate nuclear explosion effects.”

8. E8 Bombing Bombay? - International Physicians for the Prevention of Nuclear War (IPPNW Global Health Watch Report Number 3) International Physicians for the Prevention of Nuclear War (IPPNW); author M.V. Ramana, MIT · 1999

   “Based on the data from Hiroshima, this report estimates the number of casualties from these different sources of injuries. Depending on the population density in the part of the city that is targeted, the numberod deaths would range between 160,000 to 866,000 for a 15 kiloton explosion — approximately the same destructive power as the weapon dropped on Hiroshima in 1945.”

9. E9 Bombing Bombay? - International Physicians for the Prevention of Nuclear War (IPPNW Global Health Watch Report Number 3) International Physicians for the Prevention of Nuclear War (IPPNW); author M.V. Ramana, MIT · 1999

   “A 150 kiloton weapon — typical of more modern hydrogen bombs — could cause somewhere between 736,000 and 8,660,000 deaths.”

10. E10 Bombing Bombay? - International Physicians for the Prevention of Nuclear War (IPPNW Global Health Watch Report Number 3) International Physicians for the Prevention of Nuclear War (IPPNW); author M.V. Ramana, MIT · 1999

    “Nevertheless, it is clear that about 150,000 to 800,000 people will die within the first few”

E8, a 1999 IPPNW report by M.V. Ramana, estimated that a 15-kiloton Hiroshima-scale explosion over Bombay would kill between 160,000 and 866,000 people depending on population density. That upper end, 866,000 deaths, approaches but does not reach 1 million for a single 15-kiloton, Hiroshima-scale explosion in a city [E8]. The same report (E9) put deaths from a single 150-kiloton weapon in the city at up to 8,660,000. So a credible published analysis available before October 2005 reached roughly 1 million or more fatalities, although other estimates such as the OTA Detroit case (E4, 470,000 deaths) were lower.