Cover-up of Injuries from Atomic Bombing
and Severe Effects of Internal Exposure to Residual Radiation
Shoji Sawada
Present Situation of Atomic Bomb Survivors and Estimation of Radiation Effects
Now, after sixty-five years of Hiroshima and Nagasaki atomic bombing, many atomic
bomb survivors are still suffering aftereffect diseases. The Japanese government has
provided special medical and livelihood assistance to survivors whose diseases areverified to be from the effects of the atomic bomb radiation, however, the criteria
adopted by the subcommittee of Atomic Bomb Survivors Medical Care of the Ministryof Health, Labor and Welfare are very strict and far removed from the actual situation ofmany survivors. The numbers of legally accepted atomic bomb survivors who hold ahealth note book was 380,000 in 1980 and the number of survivors who were certified
as suffering from diseases caused by the atomic bomb radiation effects by the Japanese
government was 4,400 at that time. After 1980, the number of certified survivors rapidly
decreased from above 4,000 to about 2,000 which was less than 0.8% of the total
survivors of 270,000 in 2003 reflecting only the political and financial grounds of thegovernment. Now a collective lawsuit has been going on from 2003 in 17 local courts
by 306 atomic bomb survivors against the Japanese government demanding withdrawal
of rejection of application to certify atomic bomb disease. Prior to the collective lawsuit
seven successive judgments including those by the Supreme Court and by two highcourts had pointed out that the criteria for atomic bomb disease certification by thegovernment is not consistent with the actual conditions of survivors and decided towithdraw the rejections. However, the Japanese government had introduced more severe
criteria about probability of causation by which even the applications of survivors who
got favorable judicial decisions will be also rejected.
The criteria, the probability of causation, of atomic bomb disease certification has
been based on the Atomic Bomb Radiation Dosimetry System 1986 (DS86) and resultsof the epidemiological research that has been done at the Radiation Effect Research
Foundation (RERF) which is the successor of the Atomic Bomb Casualty Commission(ABCC). The epidemiological survey of RERF put emphasis only on the initialradiation (gamma rays and neutrons ) which were emitted within 1 minute after the
explosion and the effects of the residual radiation had not been considered. The initialradiation had caused acute external exposure meaning irradiation from outside of human1body. There are two sources for the atomic bomb residual radiation; one is from radioactivated matter induced by the initial neutrons and the other is the radioactive fallout
which include the fission products, neutron-induced equipments of the atomic bombs
and fissile materials (uranium and /or plutonium) leaving without fission. Beyond
external exposure effects, the major effects of residual radiation are chronic internal
exposure due to intake of radioactive matter by respiration, ingestion and other forms.
The nuclear weapon states, among which the US takes a leading role, have hidden thesevere effects and inhuman character of internal exposure, in order to maintain theirarguments that the injuries from a nuclear explosion can be restricted. The International
Commission on Radiological Protection (ICRP), which has set international standardsof radiation protection, has been influenced by the policies of governments of the US
and Soviet Union and especially has relied on the epidemiological studies of RERF.
Then the international standards of radiation protection set by ICRP have the sameproblems. Therefore to clarify the severe effects of internal exposure from the scientificstandpoint is an important task for the future of human beings.
After 6 successive lost cases of the collective lawsuit the Japanese government
revised their criteria for atomic bomb diseases by abolishing the probability of causation
and accepted the effects of exposure to residual radiation in March 2008. On thememorial day of Hiroshima, 6 August this year, after 19 successive lost cases including
5 decisions of higher courts, the prime minister signed a note of confirmation with theJapan Confederation of A- and H-Bomb Sufferers Organizations, which have promoted
the collective lawsuit. In the note the government promised that the government will be
subjected to decisions of local courts and withdrew appeals to the higher courts.
Cover-up Policy of the US on Nuclear Injuries
Just after the beginning of Japan’s occupation by the Allied Forces, on 6 September
1945, a brigadier general T. Farrel, who was a commander of the research commissionof the Manhattan Project gave a press interview and published a statement that "In
Hiroshima and Nagasaki, at present, the beginning of September, anyone liable to die
has already died and no one is suffering from atomic radiation."

This was disputed bya journalist W. Burchett who had seen the real state of Hiroshima, where one hundred
survivors died each day. Farrel made a counterargument that denied the facts: "In orderto remove risk from residual radiation the bomb was exploded at considerable altitude,
so it is impossible that radioactivity exists in Hiroshima at present, and if someone died2

at present it will not be owing to residual radiation but from the effects of damage
received at the time of bombing. "Farrel was in charge of research on the human effectsof radiation including experiments on the human body in the Manhattan Project so hewould already have known that if a few fine radioactive particles accumulate in the lungit produces fatal effects.
On 19 September 1945, the General Headquarters of the Allied Forces issued apress code that controlled by severe inspection press reports and literature concerning
the atomic bomb and by demanding permission before publication of research results on
the damage of atomic bombing, practically forbidding publication. This was the
beginning of the US cover-up policy regarding radiation damage, especially of the
problems of internal exposure to residual radiation.
All the results obtained by Japanese scientists just after the bombing and the resultsof research done by the Special Committee for Investigation and Research on Injuries
from the Atomic Bomb established by the Japanese Academic Council were brought toAmerica. Late in September 1945 the US Army and Naval surgeon group organized the
Joint Commission for the Investigation of the Effects of the Atomic Bomb in Japan bymaking the Medical Faculty of Tokyo Imperial University the collaborator andinvestigated for about one year, but they carried back to the US all collected materials.
ABCC and RERF
The US, having decided to dominate the world with nuclear weapons, had been
compelled to study, from both offensive and defensive aspects, effects on the humanbody of use of nuclear weapons, especially of the effects of initial radiation. On 26
November 1946, President Truman ordered establishment of a Commission on Atomic
Bomb Casualties (CAC) and the CAC decided to found Atomic Bomb Casualty
Commission (ABCC).

After preparatory investigations the ABCC built permanent

institutions at Hiroshima and Nagasaki in 1950 and began investigation of atomic bomb
survivors. In interviews investigating the experiences of survivors the ABCC made athorough examination of the exposed place (indoors or outdoors, thick or thin shelteredhouse, etc.) and of the posture of the survivor at the instant of bombing in order toestimate exposed dose from the initial radiation of the atomic bomb. On the other hand,
the ABCC did not inquire into the behavior of survivors after the explosion which wasnecessary to estimate residual exposure for the survivor.
Due to the occupier’s closed manner of the ABCC and frequent change of American3

expert staffs as well as bad feeling among citizens of Hiroshima and Nagasaki, theactivities of the ABCC stagnated around 1955. Following the Francis Committee’s
recommendation based on the examination of ABCC activities, the ABCC restarted the
Adult Health Study (AHS) on about 20,000 survivors in 1958 and the Life Span Study(LSS) on about 100,000 survivors in 1959. At long last in 1975 the ABCC was closed
and the RERF was started up, but the ABCC’s staff, institutions and projects were left tocontinue under the RERF as well as intrinsic problems of the ABCC. The
epidemiological research in the RERF remains unchanged completely ignoring theeffects of residual radiation.
The Bikini H-Bomb Tests and Studies on Radiation Damage
A hydrogen bomb test Bravo Shot at Bikini atoll of Marshall Islands on 1 March 1954
made a very big impact on the Japanese people. A nationwide movement against nuclear
weapons arose and the first World Conference against A & H Bombs was held in August
1955 at Hiroshima. On the basis of this movement many scientists and experts invarious fields, such as radiation physics and chemistry, radiobiology and fisheriesscience, took an active part in investigation of health effects from the Bikini nuclear
tests and clarified that the effects from fallout of hydrogen bomb tests had been spreadover a wide region of the Pacific Ocean. These investigations and researches byJapanese scientists pointed out that the radiation effects of fallout from these nuclear
tests were very severe. Reflecting these findings the Russell-Einstein Manifesto in 1955
pointed out the dangerous situation of radioactive fallout:"... Such a bomb, if exploded near the ground or under water, sends radioactive
particles into the upper air. They sink gradually and reach the surface of the earth in theform of a deadly dust or rain. It was this dust which infected the Japanese fishermen andtheir catch of fish.
No one knows how widely such lethal radioactive particles might be diffused, but
the best authorities are unanimous in saying that a war with H-bombs might quitepossibly put an end to the human race. It is feared that if many H-bombs are used there
will be universal death--sudden only for a minority, but for the majority a slow tortureof disease and disintegration."
Exposure of Marshall Islands People
In the case of the Bikini test, not only the crew members of the 5th Lucky Dragon boat4

and the inhabitants of Rongelap atoll but all the people of Marshall Islands were
exposed simultaneously to radiation from fallout. Although the inhabitants had received
strong exposure from fallout they were left unattended for a while. Moreover, in 1967
inhabitants of Rongelap atoll were brought back by the US army to their atoll becauseof “absence of radioactivity”. However due to frequent occurrence of injuries among
inhabitants including those not exposed to fallout, they departed by themselves again
from their atoll in 1985. Recently it was found that the US Atomic Energy Commission
which conducted these nuclear tests had made a thorough observation of radiation fromfallout during these tests but did not open the observed results to the public.
Even now inhabitants of Rongelap atolls are forced to leave and robbed of their own
birthplace for more than half a century. When the Marshall Islands Republic became
independent in 1989, it concluded a Free Alliance Agreement with the US which
includes compensation for the use of Kwajalein atoll, the largest atoll of MarshallIslands, as a military missile test site plus compensation for the damage from nuclear
tests. In the 2004 revision of this agreement, compensation for nuclear test damage wasdiscontinued by the US who asserted that there are no effects of residual radiation.
In Fig. 1 an investigation of abnormal births among Marshallese show that the rateof abnormal births in each atoll of the Marshall Islands decreases with distance from

Figure 1. Abnormal Birth Rates among Marshallese Islanders
5

Bikini atoll and clearly indicates that effects of fallout of nuclear tests extend to thewhole region of Marshall Islands (The average rate of abnormal births among MarshallIslands women before the nuclear tests was 0.04.) Now the people who were inhabitantsof the severely contaminated atolls, Enewetok, Rongelap, Utrik and Bikini atolls, set up
an organization ERUB on the occasion of the 50th anniversary of the Bravo Shot andbegan a petition for compensation to the US Congress.
Revision of Dosimetry System of Atomic Bomb Radiation from DS86 to DS02
It is necessary to estimate the exposed atomic bomb initial radiation dose of survivors
for the epidemiological studies by the ABCC and RERF. For this purpose the US had
made an estimation of radiation dose, the T57D (Tentative Dose 1957) and the T65D
(Tentative Dose 1965), on the basis of nuclear tests. The atomic bomb dosimetry system
DS86 is the first computer calculated estimation of the initial radiation dose from theHiroshima and Nagasaki atomic bombs. The DS86 put emphasis on the initial radiation
reached at short distances and showed little concern for, or neglected, residual radiationfrom fallout and induced radioactive matter.
The Dosimetry System 2002 (DS02), a substitute of the DS86, was published in
2005. In the DS02 in order to rectify an over estimate of initial radiation doses at shortdistances in the DS86 the height of explosion of Hiroshima bomb is changed from580m to 600m and the yield of explosion from 15 ktTNT to 16 ktTNT. Leaving aside
the problem of a discrepancy between estimated values from the DS86 system andexperimentally measured values in the distant region without further explanation, thepreparation of DS02 is justified by a US side argument that measured values at greater
distances include natural background radiation effects other than bomb radiation. The
DS02 did not contain a single description of the residual radiation.
Since the estimation of initial radiation (both of gamma rays and neutrons) frommeasurements systematically exceed the estimation of the DS86 and DS02 in the region
more distant than 1.5 km from the hypocenter and the discrepancies increase with
distance, the DS86 and DS02 estimates cannot be applied to the distance beyond 1.5 km
from the hypocenter of atomic bombing even confined to the initial radiation.
Physical Consideration of Internal Exposure
Among fallout of the atomic bomb of Hiroshima and Nagasaki (1) 3.6
fission products, (2) (2—5)

1024 nuclei of1024 nuclei of neutron-induced radioactive matter of6

bomb fragments and casing, (3) 1 1026 nuclei of uranium-235 or 2.5 1025 plutonium
239 which did not participate in the fission chain reaction were included respectively.
After explosion of each atomic bomb a fire ball of plasma was formed and allradioactive nuclei listed above were included in this. The fireball turned into themushroom cloud. The central part of cloud rose breaking through the tropopause up to
15 km or more and the peripheral part of cloud spread along the tropopause over a
region with radius more than 15~20 km. The region where fine particles of the fallout
fell can be assumed to have been larger than the region covered by the mushroom cloud.
In the fallout a huge number of fine particles were included which had been containedin the fireball.
The atomic bomb survivors were externally exposed by initial radiation fromoutside their bodies. This exposed dose can be estimated roughly if the location of thesurvivor is known. Survivors and people who entered the regions near the hypocenter
were also exposed to radiation emitted by residual radioactive matter induced by the
initial neutron beam. The doses experienced by survivors from the induced radioactive
matter can be estimated roughly by use of physical calculations and measurement data if
their actions or behaviors were known. It is difficult, however, to estimate the radiationdose of fallout in terms of physical measurement long after the explosion because mostof the fine particles of the fallout were carried by the wind and the radioactive matteraccumulated on the surface of the earth or sank into the earth which had been broughtby so called black rain or other form of fallout were washed away by heavy rainsaccompanying typhoons. It is more difficult to estimate the effects of internal exposure
by inhalation or ingestion of radioactive matter of the fallout and/or induced matter byphysical methods.
When some radioactive substances are taken into the body, if they are water or oilsoluble then they will spread throughout the whole body at the level of atom ormolecule and some radioactive materials will concentrate and/or deposit in specialorgans depending on the types of chemical elements. For example, iodine concentrates
in the thyroid, and phosphorus and cobalt are concentrated in bone marrow. In this caseamounts of absorbed radioactive materials taken into body can be estimated fromexcrement such as urine. By contrast, if insoluble radioactive fine particles are absorbed
there are possibilities that the fine particles are deposited in some organ while
preserving their size and that radiation emitted from these fine particles irradiatecontinuously and intensively surrounding cells. In this case it is difficult to detect these7radioactive particles from outside the body and also to estimate them from excrements.
Effects from such radioactive fine particles largely depend on their size and also on thetype of radioactive elements and type of radiation (the average life-time and alpha, beta
or gamma ray). It is difficult to represent these effects in terms of a simple factor suchas the absorbed energy per weight, the unit of absorbed dose, Gy, or by use of therelative biological effectiveness, the unit of equivalent dose, Sv. The difference between
external uniform exposure and internal exposure by a radioactive fine particle isillustrated in Fig. 2. Therefore the biological estimation of effective exposure dose
which includes both external and internal ones is required on the basis of analyses of theinvestigation of incidence rates of the acute and clinical radiation diseases and the rateof chromosomal aberration especially where it appears among distant survivors andentrant survivors who were not severely exposed to the initial radiation.

Figure 2. External and Internal Exposure to Radiation
Estimation of Residual Radiation in Terms of Incident Rate of Acute Radiation
DiseaseIn order to estimate actual effects of both initial and residual radiation it will be usefulto analyze examined data of acute radiation disease among survivors of the atomic
bombings in Hiroshima and Nagasaki.
Around 1950 the ABCC obtained incidence rates for the heavy epilation (above
67 % hair loss) which appeared within 60 days after the detonation of the bomb. Preston
et al of RERF reported separately the incidence rates of epilation of Hiroshima and8Incident Rates of Epilation (Hiroshima)

80

Stram-Mizuno(Primary Rad.)
Fit to Stram-Mizuno(Primary Rad)
ABCC-RERF-LSS(Hiroshima)
Fit to ABCC-RERF-LSS(Hiroshima)

70

60

Incident Rates

％

50

40

30

20

10

0
0

Figure 31234Distance from Hypocenter km

5

6Incident Rates of Epilation among the LSS Hiroshima Group

Nagasaki survivors among the LSS group. Preston et al reported the dependence of theincidence rates of epilation of 58,500 Hiroshima survivors among the LSS on distancefrom the hypocenter which is shown by squares in Fig. 3 (D. L. Preston, et al. Magazine
of Nagasaki Medical Society (in Japanese)). Incidence rate 100 % at 0.75 km is scaleout from this figure. Although the initial radiation could scarcely have reached beyond 2
km from the hypocenter, small but non-negligible rates of epilation occurred.
From incidence rates among the LSS group Stram and Mizuno of the RERF
derived a relationship between absorbed dose of acute exposure from the atomic bomb
9

Relationship between Incidence Rate of Epilation and Exposed Dose

100
90
80

％

70

Incidence Rate

60
50
40
30

Incident Rate of LSS by SM (%)
Modified Distribution of LSS
Fit by Normal Distribution
Transplant Experiment by Kyoizumi et al
Fit by Normal Distribution
LSS-Hiroshima Group

20
10
5%
0
0

Figure 4

1

1.44

2

3
4
Exposed Dose Gy

5

6

7

Relation between Incidence Rate of Epilation and Exposed Dose

initial nuclear radiation and the incidence rates of epilation based on the assumption that
epilation in the distant regions was caused by background effects other than radiation,such as mental effects. Results obtained by Stram and Mizuno of incidence rates among
the LSS group for initial radiation dose estimated by the Dosimetry System 1986
(DS86) are shown by small closed circles in Fig. 4 (Radiation Research 117, 93113(1989)). As shown in Fig. 4 the incidence rate rapidly increases above 1 Gy andexceeds 50 % at around 2.4 Gy. However, beyond 3 Gy the rates do not increase andeven decrease as dose approaches 6 Gy. This unnatural behavior of the incidence rates
in the high dose region can be explained by the fact that the LSS group contains only
people who were left alive in 1950 though they had been exposed to nearly or more thana half-death dose of about 4 Gy as pointed out by Stewart et. al.(Health Phys. 58, 782735 (1990): 64, 467-472 (1993); Int J Epidemiology, 29, 708-714 (2000)) as well asover subtraction of background incidence rates.
Incidence rates of epilation shown by open circles in Fig. 4 are those obtained by
Kyoizumi et al. (Radat Res 194, 11-18 (1998); RERF Update 7(2);4-5(1995)) by means10

of radiation exposure to transplanted human head skin onto immunodeficient mice. As
seen in Fig. 4 the incidence rates increase very slowly in the low exposure region
compared to those given by Stram and Mizuno and increase to 95.5 % and 97 %, andalmost 100 % at exposure of 4.5 Gy. From experimental studies with animals it is
known that most of dose dependence of incidence rates or death rates are represented bya Normal(Gaussian) distribution. The incidence rates given by Kyoizumi et. al. over thewhole range of the exposure region can be fitted well by the normal distribution with an
expectation value of 2.751 Gy and standard deviation 0.794 Gy and shown by a solid
curve in Fig. 4. At this expectation value 50% of people will experience epilation.
When it is recognized that the results of Stram and Mizuno shown in Fig. 4 wereobtained from examination data of the LSS group based on the assumption that theepilation was caused only by the exposure to initial radiation regarding the fallout
radiation as the background, it is expected that the black circles in Fig. 4 shift towardhigher dose and higher incident rates, i.e. toward the relationship obtained by Kyoizumi
et al as shown by arrows if the exposure to the fallout radiation is included. When the
exposures indicated by black circles in Fig. 4 for initial radiation dose are translated into
distance from the hypocenter by use of the DS86 estimation neglecting shielding effects,
we obtain results which are plotted by black diamonds in Fig. 3. If the shielding effects
are taken into account the diamonds shown in Fig. 3 will move to the left towards the
hypocenter and the distance between the squares will increase. It is assumed that thesystematic difference between squares and diamonds shown in Fig. 3 represents
exposed effects from fallout radiation.
By use of the relationship given by Kyoizumi et al, total exposure at 2 km from the
hypocenter of Hiroshima can be obtained as follows. The incidence rate of epilation at 2
km is about 5% as seen in Fig. 3. From the relationship of Kyoizumi et al shown in Fig.
4 this 5% rate corresponds to exposure of 1.44 Gy. The initial radiation exposure isestimated as 0.04 Gy by assuming the shielding effect is 0.5. Then the exposure fromfallout is estimated as about 1.4 Gy. By use of a similar statistical method the exposed
effects from the radiation of the Hiroshima atomic bomb are obtained as shown in Fig. 5from the incidence rates of epilation among the LSS Hiroshima group. The doses of
total, initial nuclear radiation and fallout exposure are shown by a bold dashed curve, athin dashed curve and a bold solid curve, respectively and the initial nuclear radiation
doses estimated by DS02 are also shown by a thin solid line in Fig. 5. As seen in Fig. 5,
the effects of fallout exposure increase with distance from the hypocenter up to 1 km,
11but this has large ambiguity because the incidence rates in the region below 1 km were
not employed in the present analysis. Exposure from the initial radiation rapidly
decreased with distance from the hypocenter and at about 1.2 km the fallout effects
cross over that of initial nuclear radiation and beyond this distance the fallout effects
become dominant. The estimated exposure from fallout radiation reaches about 1.5 Gy
at around 1.45 km then decreases slowly. Beyond 4 km the exposure effect of fallout
takes an almost constant value of 0.79 Gy. This result from the incidence rates of
epilation, one of the actual accepted and universally agreed conditions of the bombed

3

Exposure to Radiation of Hiroshima Bomb from Incidence
Rates of Epilation
Fallout Exposure (Kyoizumi etal)
Primary Exposure (Kyoizumi eyal)
Total Exposure (Kyoizumi etal)
Primary Radiation Dose by DS02
Max. Fallout Exposure fron 'Brack Rain'
系列9
系列10
系列11

2.5

2
Exposed Dose

Gy

Exposure
to Initial
Radiation

Estimation of Total
Exposed Dose from
Incidence Rates of
Epilation

1.5

InitialRadiation
by DS02

1
Exposure
to Fallout
Radiation

0.5

Max. Dose Estimationfrom 'Brack Rain' KoiTakasu Area
0.006~0.02 Gy

0
0

1

2
3
4
5
Distance from Hypocenter km

6Figure 5 Exposure of Hiroshima Atomic Bomb Radiation Estimated from
Incidence Rates of Epilation among LSS Hiroshima Group12

survivors, indicates overwhelming effects of fallout beyond about 1.5 km from the
hypocenter of Hiroshima. For example at 2.25 km and 2.75 km from the hypocenter thedose estimation of the initial radiation by DS02 are 0.0302 Gy and 0.0053 Gy while theincidence rates of epilation among the LSS-Hiroshima group at these distances are
3.5 % and 2.1 %. The estimated fallout exposure effects from these incidence rates are
1.34 Gy and 1.16 Gy, about 44 and 219 times the DS02 initial radiation.
The maximum cumulative exposure from fallout of the Hiroshima bomb has been
considered hitherto between 0.006 and 0.02 Gy in the Koi-Takasu region mentioned in
the DS86 report and adopted by the Japanese government as the criteria of atomic bomb
diseases which are shown by cross marks in Fig. 5. These absorbed doses were obtained
from measurement of radiation from fallout matter retained in the soil of these regions
which are located between 2 and 4 km to the west of the hypocenter where lightradioactive fallout rain fell but heavy rain caused by the big whole city fire did not. As
seen in Fig. 5 exposure from fallout estimated from epilation incidence rates in the 2 to
4 km region are 1.4 Gy to 0.85 Gy which are 40 to 230 times the physically obtained
values. This large discrepancy suggests that the physically measured values are only
measurements of a part of fallout and that large effects of internal exposure should betaken into account which can be deduced only by biological methods. It is noteworthy
that the values obtained here are average exposures in the same distant regions from the
hypocenter irrespective of direction. This result supports the understanding that fallout
particles were distributed in the air very widely under the mushroom cloud.
There are many examinations of incidence of epilation, for example by the Joint
Commission for the Investigation of the Atomic Bomb and Tokyo Imperial University
in 1945 and investigated by a medical doctor O-ho in 1957. These examinations give
results that almost coincide with each other indicating the reliability of all theseinvestigations. Then from analysis of incidence rates of epilation of these examinations
almost the same results are obtained.
.
Comparison of Fallout Exposure Estimated from Incidence Rates of Three Different
Acute Diseases
The incidence rates of epilation, purpura and diarrhea among Hiroshima survivors who
were exposed indoors and did not enter the central region examined by O-ho (G. O-ho;
I-Ji Shinpo, No.1746,21-25(1957)) are shown in Fig. 6. As is seen in Fig. 6 incidence
rates of purpura shown by closed circles are of similar behavior to those of epilation
13

shown by squares. Then for the relationship between incidence rate of purpura andexposure dose the same normal distribution for epilation is used. Incidence rates ofdiarrhea shown by triangles are very large compared to epilation or purpura in the
distant regions beyond 1.5 km where the fallout exposure produced significant effects.
The incidence rates of diarrhea were rather small in the short distance regions where theinitial radiation exposure dominated. Therefore in the case of diarrhea, a larger
expectation value for the normal distribution than those of epilation and purpura isrequired for external exposure from the initial nuclear radiation, and a smaller
expectation value is required for the fallout exposure. The adapted normal distributions
for the relationship between incidence of diarrhea and exposed dose have an expectation
value of 3.026 Gy and standard deviation 0.873 Gy for the initial radiation and an
expectation value of 1.981
Incidence Rates of Acute Diseases in Hiroshima(O-ho)80
Depilation (O-ho)
Fit to Inc. Depilation
Purpra (0-ho)
Fit to Inc. Purpra
Diarrhea (O-ho)
Fit to Inc. Diarrhea
系列19
系列20
系列21
系列22
系列25
系列27
系列28
系列29
系列38
系列39
系列40
系列41
系列42
系列43
系列44
系列45
系列46
系列47
系列56
系列57
系列58
系列59
系列60
系列61
系列62
系列63
系列64
系列65
系列67
系列68
系列1

70

％

50

Incident Rate

60

40

30

20

10

0
0

Figure 6123Distance from Hypocenter

4
km

5

Incidence Rates of Acute Diseases examined by O-ho among Hiroshima
14

Survivors Bombed Indoors and Who Did Not Enter the Central Regions
Gy and standard deviation 0.572 Gy for the fallout radiation, respectively. By use of
these normal distributions the incidence rates of epilation, purpura and diarrhea in Fig. 6
are fitted and the resulting incidence rates are displayed by thin dashed, solid and chain
curves for epilation, purpura and diarrhea as shown in Fig. 6.
The results of exposure doses obtained in order to reproduce these three different
acute diseases are shown in Fig. 7 by bold broken lines, thin broken lines and bold fulllines for total, initial and fallout radiations, respectively given the same marks as in Fig.
6. As seen in Fig. 7 incidence rates of three entirely different acute diseases are
reproduced with high accuracy by almost the same exposure doses. This fact tells usthat epilation and diarrhea as well as purpura occurred in the regions where the initialradiation could scarcely reach, and were caused by fallout radiation not by mental shock
nor by poor sanitary conditions.
Exposed Doses from Acute Diseases（O-ho）4Primary Radiation (DS02)
Total Exposure（epilation)
Primary Exposure（epilation)
Fallout Exposure(epilation)
Total Exposure（purpura）
Primary Exposure（purpura）
Fallout Exposure（purpura）
Total Exposure（diarrhea)
Primary Exposure（diarrhea)
Fallout Exposure（diarrhea)

Exposed Dose Gy

3

2

1

0
0

Figure 71234Distance from Hypocenter km

5Exposed Doses of Hiroshima Atomic Bomb from Three Different Acute

Diseases
15

The fact that the expectation value of the normal distribution of diarrhea incidence issmall for fallout exposure while large for the initial nuclear exposure can be explainedby means of the difference between external and internal exposures as follows. In thecase of fallout exposure radioactive fine particles and radio-nuclides with specificaffinity for biological materials and tissues among fallout were taken into the body,reached the intestinal wall and were retained there for a period of time. Then the emitted
radiation of weak penetration power produced dense ionizations and caused heavy
damage to the thin membrane and diarrhea followed. The exposure was chronic as theparticulate and chemical radio-isotopic material (e.g. Sr-90, Cs-137) was retained forsome time. On the other hand in the instantaneous acute initial nuclear radiation
exposure case only strong penetrative radiation such as gamma rays could reach fromoutside the body to the intestinal wall but passed through the thin membrane leaving
scarcely any damage. The present result of fallout effects shows that fallout came downover very wide regions under the atomic cloud as illustrated in Fig. 8.
The RERF epidemiological study selected as the control cohort (non exposure group)for practical purposes those among the survivor group who were exposed to a radiationdose estimated as less than 0.005 Sv on the basis of the DS86 or DS02 systems.
The RERF epidemiological study selected as the control cohort (non exposuregroup) for practical purposes those among the survivor group who were exposed to a

Figure 8 Fallout Rain Fell in the Special Regions under Central Part of the Cloudand Atmosphere under Cloud were Filled with Radioactive Fine Particles.
16According to the estimation of DS86, survivors included in the control cohort werebombed in the region more than 2.7 km from the hypocenter, and these survivors
received effects by fallout radiation equivalent to external acute exposure to gamma
rays of about 1.5 Gy on average as shown in Figs. 5 and 7. These effects are 300 times
the initial radiation estimated by the DS86 system. This will explain why thegovernment criteria for atomic bomb diseases differs so much from actual states ofsurvivors who have suffered after effects of atomic radiation for 64 years.
Radiation Effects for Entrants after the Bombing
The incidence rates of acute radiation disease were examined by G. O-ho (ibid) among
the people who entered from the day after the bomb exploded to after 34 days in theregion within 1km from the hypocenter of Hiroshima. From analysis of the incident
rates exposure effects for entrant people are estimated. For the entrant on the day of the
explosion (6 August) the accumulated exposed effective dose for onset of acuteradiation disease is equivalent to external acute exposure to gamma rays of 1.05

0.53

Gy. The accumulated exposed effective dose exponentially decreases to almost half for
those who entered the central region 9 to 10 days after the day of the bombing.
Accumulated exposure dose received from external radiation induced by neutrons canbe calculated for staying at the hypocenter, and at 0.5 km and 1 km from the hypocenter.
Even at the hypocenter the accumulated exposed dose from external radiation is 0.8 Gy,
those at 0.5 km is 0.09 Gy and 0.0017 Gy at 1 km. The large discrepancies between
exposure effects estimated from acute radiation disease among the entrants after
bombing and measured external accumulated dose suggest that effects of residual
radiation from chronic internal exposure due to inhalation of radioactive matter werevery large compared to those of external exposure.
As is shown by analysis of the incident rate of the acute radiation diseases,
however, for the survivors bombed in the region beyond 1.5 km the effects of internal
exposure of radioactive fallout are more severe than the effects of external exposure by
the initial radiation. Therefore application of DS86 or DS02 for the estimation of
exposure of distant survivors and the entrant survivors is a complete mistake.
Estimation of Residual Radiation from Chromosomal Aberrations
When one is irradiated, abnormalities appear among chromosomes in the irradiatednuclei of a cell. Since this frequency of chromosomal aberration is closely related to the17exposed dose,the frequency of chromosomal aberration in circulating lymphocytes

provides an estimation of averaged absorbed dose in survivors. M. Sasaki and H.
Miyata (Nature 220,1189-93,(1968)) investigated the frequency of chromosomal
aberration in circulating lymphocytes of survivors of the Hiroshima atomic bomb andeleven non-irradiated healthy people as a control who were visiting the Japan Red Cross
Central Hospital in Tokyo between April 1967 and March 1968 and found that theaberrations occurred even when the initial radiation was scarcely reached.
Fig. 9 shows internal dose estimated from chromosomal aberration among
survivors by Sasaki and Miyata. The obtained dose beyond 2.5 km from the hypocenterof Hiroshima cannot be explained by the initial radiation. In Fig. 9, the open markers
correspond to the dose obtained from frequency of stable chromosomal aberrations andthe closed ones to those obtained from unstable aberrations. The broken curves are
Radiation Effects from Chromosome Aberrations
Sasaki and Miyata

Average Dose

cGy

100

10

1
0.0

0.5

1.0

Outdoors Qdr-type
Outdoors S-type
Wooden house S
Wooden house Qdr
Concrete S-type
Concrete Qdr-typeDistant S
Distant Qdr
系列9
系列10
系列11
Initial系列12Rad.(DS02)
系列13
Initial系列14Rad.(DS86)
Initial系列15Rad.(T65D)
系列16
Fallout
from S-type
系列17
系列18 S-type
Initial+Fallout
系列19
Fallout
from Qdr-type
系列20
系列21 Qdr-type
Initial+Fallout
系列22
系列23
系列24
系列25
系列26
系列27
系列28
系列29
系列30
系列31
系列32
系列33
系列34
系列35
系列36
系列37
系列38
系列39
系列40
系列41
系列42
系列43
系列44
系列45
系列46
系列47
系列48
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
系列49
系列50
Distance from hypocenter km
系列51
系列52
系列53
系列54
系列55
系列56
系列59
系列60
DS02
fallout
primary

Figure 9 Radiation Effects from Chromosome Aberrations by Sasaki and Miyata
obtained by chi-square fitting to the estimated exposed dose of survivors who had been
exposed outdoors at distances of less than 2.2 km from the hypocenter (denoted by18

triangles) and at 2.4 km or more away (denoted by circles). The initial radiation dose
given by the T65D and DS86 are denoted by almost straight lines, dashed and solid ones,
respectively. The broken curves are obtained by subtraction of the contribution of theinitial radiation given by DS86 from the solid curves and can be attributed to the effectsof fallout contribution. The peak values 0.06 Gy and 0.3 Gy obtained from unstable andstable chromosomal aberrations exceed the initial radiation dose at 2.0 km and 1.6 km,
respectively from the hypocenter. In the regions beyond these distances the effects of
exposure by fallout exceed those from the initial radiation. It should be noted that theestimated dose based on the frequency of chromosomal aberration in circulating
lymphocytes represents the effects averaged over the whole body and do not include
local effects from the insoluble radioactive fine particles which are considered in thecase of the analysis of the incidence rates of acute diseases.
The chromosomal aberration of a larger sample of survivors had also been
investigated by the RERF study group 23 years after the bombing and the RERF havedenied the existence of chromosomal aberration in the distant region. In the RERF
investigation, however, the distant survivors with dose estimation <0.01 Gy and theentrant survivors who were not in the city at the explosion time (NIC) were used as thecontrol group. The frequency of chromosomal aberration of this control group is morethan four times the control figure used world-wide and about ten times that used by
Sasaki and Miyata.
Problems in RERF Epidemiological Studies
There are serious problems in the epidemiological studies of the RERF when the resultsof the studies are applied to survivors. One is neglect of the contribution from theresidual radiation for the estimation of exposed dose of survivors. This originated in theinitial investigation of survivors done by the ABCC. The other serious problem isselection of a non-irradiated control group. The epidemiological studies by the ABCCRERF have been adopted by survivors themselves as the non-exposed control cohort forthe studies. In the recent RERF investigations the survivors who had been exposed toless than 0.005 Sv of the DS86, and the NIC group in which the early entered survivors
are included, are used as the control group. As is shown in the preceding sections these
distant and entrant survivors were affected by the residual radiations estimated at morethan 0.5~1.5 Gy on average which is several hundred times 0.005 Sv. Then it is evident
that the ABCC-RERF studies cannot be applied to the estimation of exposure for distant19

and entrant survivors.
The analysis of chronic diseases among the RERF control cohort by use of all
Japanese as the control was made by Inge Schmitz-Feuerhake, a physics professor ofBremen University, Germany and deduced the effects of exposure from fallout and theinduced radioactive matter. Her result of the analysis is given in Fig. 10 (Health Phys.
44,693-695 (1983)). The high relative risk of both mortality and incidence of leukemia,
thyroid, female breast cancer and respiratory system cancers among the control cohorts
Relative Risk of the Control of RERF
All Causes

系列1● 0--0.09 Gy Group
系列2○ Entrant Group
Trauma系列3系列4系列5
All Disease 系列6系列7系列8Tuberculosis
系列9
系列10
系列11
All Mmalig. 系列12
Neoplasms系列13
系列14
系列15
Leukemia 系列16
系列17
Early Entrants
系列18
Repiratory 系列19
System
系列20
系列21
系列22 Ex.
Digestive System
系列23
Stomach 系列24
系列25
Benigm & Unsp.
系列26
Neoplasms系列27
系列28ofVascular Lesions
系列29
CNS
系列30
Circulatory系列31
System
系列32
Disease
系列33
系列34
系列35
↑ Mortality
系列36↓ Incidence
系列37
系列38
Female Breast, Inc.
系列39
4.1
50-74
系列40
系列41
Thyroid, Inc. 50-71
系列42
系列43
3.4
LEUKEMIA, 系列44
Inc. 71-75
系列45
系列46
系列47
0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8
系列48
Relative Risk

Figure 10

Relative Risk of Controls of RERF
20

of the RERF epidemiological study (both distant and after entrant survivor) had been
affected by fallout and residual radiation. If the early entrants (4,500 of 26,500 people
entered the cities within three days after the explosion ) among the NIC group of the
RERF investigation are extracted, then the relative risk of leukemia becomes about
twice the normal rate as shown by point Early Entrants in Fig. 10. Hirose found 45
cases of leukemia among 25,798 early entrants of Hiroshima which corresponds toabout 3.7 times the Japanese normal rate. These facts conclude that the RERF
epidemiological studies have severe basic problems concerning the choice of the control
cohorts.
Very recently T. Watanabe et al.(Environ Health Prev Med,13:264-270(2008))
compared the mortality rates of the LSS-Hiroshima group with those of the entire
populations of Hiroshima Prefecture and neighbouring Okayama Prefecture. They
divided the LSS group by colon absorbed dose into three categories: under 0.005 Sv(very low), more than 0.005 Sv and under 0.1 Sv (low), and more than 0.1 Sv (but lessthan 4.0 Sv) (high), respectively. They found that there are significantly increased risksof cancer among even survivors exposed to the very low dose level. One of their resultsof relative mortality rates from various cancers among the male group of LSS-

Figure 11

Relative Mortality of Cancer of LSS-Hiroshima Group vs Entire

Population of Okayama Prefecture21

Hiroshima Male Group vs Okayama Prefectures are shown in Fig. 11 against exposure
to initial radiation. Assuming the relative mortality rates increase linearly, regression
lines are drawn for each cancer. If there is no excess of relative mortality rates theregression curves will cross the line with relative mortality 1.0 at zero exposure point of
the initial radiation. However, the regression lines cross at negative exposure points
denotedmarks in Fig. 11. This fact means even the survivors in the very low dose
initial radiation group were exposed to fallout radiation of 0.4 to 1.0 Sv.
Therefore the results of the ABCC-RERF studies should not be applied to the criteriaof atomic diseases at the very least for distant and entrant survivors even though they
may be used to estimate external irradiation effects of the strong initial radiation.
Danger of Usable Nuclear Weapon and Earth-Penetrating Nuclear Weapon
The Bush Administration of US had decided to research and develop earth penetrating
nuclear weapons as usable. This pro-nuclear weapon policy would be largely based onignorance of, and little concern for, the damage from atomic bombing, especiallyignoring the effects of residual radiation and severe effects of internal exposure. If an
earth-penetrating nuclear weapon were used, a much greater disaster from residual
radiation would result than that experienced in the bombing of Hiroshima and Nagasaki,
where the bombs were exploded at heights of 600 and 500 meters respectively, resulting
in the radioactive fallout being somewhat weakened and the neutron beam largely
decreased before reaching the ground and inducing residual radiation.

Figure 12 Result of Use of Earth-Penetrating Bunker-Buster Nuclear Weapon22

On the other hand, an earth-penetrating nuclear weapon can penetrate only an earthpenetrating nuclear weapon can penetrate only at most 20 meters underground and thefireball produced by nuclear explosion will cause a pyroclastic flow, a stream of heatedrocks and ash, which contains various radioactive fission products and strong
radioactive matter induced by neutrons as illustrated in Fig. 12. This may cause anotherthe '21st century hell on Earth' instead of the 20th century hell on Earth, Hiroshima andNagasaki.
The 1993 UNSCEAR report estimated total deaths from cancer caused by fallout
or downwind of nuclear tests and accidents in power stations and nuclear factories
between 1945 and 1989 as 1,116,000 on the basis of the ICRP model, which had been
constructed mainly by use of the results of the RERF studies and where the effects ofinternal exposure are paid little attention. If the effects from internal exposure toresidual radiation causing cancer death are more than fifty times as severe as those in
the ICRP model, then total cancer deaths caused by fallout become more than 60 million,
which is about 1% of the total world population.
Thinking of my responsibility as a scientist and survivor of the Hiroshima atomic
bombing, if the US cover-up policy had not been enforced and scientists had clarified
the severe effects of internal exposure to the residual radiation of the atomic bombings
before frequent large scale nuclear tests, then the nuclear weapon tests would have been
forbidden avoiding great loss of human life comparable or more to that in wars.
Success for the collective lawsuit of survivors, who are dying, would contribute topromotion of the movement towards a nuclear weapon-free world by pointing out that
nuclear weapons should never be used by demonstrating the severe and inhuman natureof internal exposure as well as extraordinary acute injuries and mass murder by the heatrays, shock waves, blast and initial radiation. Especially now it is very important topublicize inhuman character of the nuclear deterrence policies which assume ultimate
use of nuclear weapon and are largest obstacles to begin the negotiation of nuclear
weapon prohibition treaty.

23