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THE FIRST ATOMIC EXPLOSION, 16 JULY 1945  
[[link removed]]


 

William Burr
July 16, 2024
National Security Archive
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_ Before Hiroshima and Nagasaki, there was Trinity, the first,
test-run atomic explosion in the New Mexican desert. The fallout is
still with us, literally and figuratively, 79 years later. This is the
story of Trinity, based on declassified documents. _

,

 

WASHINGTON, D.C., JULY 16, 2024 - On 16 July 1945, 79 years ago, the
United States, under the Manhattan Project, staged the first test of a
nuclear weapon in the New Mexican desert. The first trial of a
plutonium implosion weapon, the explosion on the ground produced
radioactive fallout contaminating over 1,100 square miles of the
state, although some debris spread as far north as Canada. Six weeks
after the test, there was a “swath of fairly high radioactivity on
the ground covering an area of about 100 miles long by 30 miles
wide,” according to a Los Alamos Laboratory report published here
for first time by the National Security Archive, while “gamma
radiation was found in measurable but very low intensities in Santa
Fe, Las Vegas, Raton and even in Trinidad, Colorado,” 260 miles from
the point of detonation.

To take note of this world historical event, the National Security
Archive today publishes declassified documents about the first atomic
bomb test and the radioactive contamination that preoccupied
government officials and medical experts during the years that
followed.

The biological and public health impact of low-level radiation is
still a contested issue, but during the years after Trinity,
researchers with the Atomic Energy Project at UCLA’s Medical School
collected evidence to help determine whether the fallout produced a
health hazard. While the studies drew no firm conclusions, a 1951
report by the Project found that there are “many potential long term
insidious hazards from the present low level contamination which is
the focal point of these studies.” The possibility that the test
could eventually produce legal action was concerning to medical
experts who were also interested in learning more about the military
implications of low levels of radiation contaminating “large land
areas,” and the Atomic Energy Commission funded the research program
at UCLA to determine the scope and impact of the contamination.

Today’s posting includes documents previously published by the
Archive demonstrating how Trinity test planners determined that the
detonation could create radioactive fallout that would spread to
nearby areas and create public health risks. New material in this
publication details preparations for possible evacuation, fallout
monitoring, the scope of the fallout, and the eventual discovery that
nearby people were exposed to potentially hazardous levels of
contamination. Also detected and studied was the impact of fallout on
farm animals that experienced beta burns
[[link removed]] on
their skin. The publication also includes several period films, such
as footage on the “100 ton” test, the “dress rehearsal” for
the atomic test, and on the Trinity test itself. 

The Trinity test took place years ago, but it is not entirely in the
past. Researchers at the National Cancer Institute have determined
that the test’s fallout contributed to excess numbers of thyroid
cancers. To this day, “down winders” in New Mexico seek federal
compensation under the Radiation Exposure and Compensation Act (RECA),
which so far has excluded that state, even though 33 of its counties,
including tribal areas, experienced levels of radiation exposure that
were higher than other U.S. counties covered by the Act.

The Trinity Test

The test was of a plutonium implosion device, the same technology that
would be deployed in the weapon that exploded over Nagasaki, Japan on
9 August 1945. Oppenheimer and his colleagues believed that a test was
necessary because the implosion technology device was so complex.
Moreover, if it failed during a combat operation the adversary could
gain control over the weapon’s costly fissile material. By contrast,
Oppenheimer saw no reason to test the “gun type” highly enriched
uranium fueled weapon that exploded over Hiroshima because its
components had been tested; for example, the first “Dragon’s Tail
[[link removed]]”
experiment confirmed the amount of highly-enriched uranium needed for
detonation. [1]
[[link removed]]

Before the 16 July test, medical specialists working at Los Alamos
alerted senior officials to the risk of contaminated dust and other
particles—fallout—that it would produce and the possibility that
dangerous levels could necessitate evacuation. With plutonium
understood to be a serious health hazard, its dispersal along with
other radioactive products was the subject of discussion weeks before
the test. A memorandum by J. O. Hirschfelder and John Magee forecast
the “definite danger of dust containing active material and fission
products falling on towns near Trinity and necessitating their
evacuation.”

While safety was not a top priority, Manhattan Project chief General
Leslie Groves wanted to avoid legal problems, which gave the need for
precautions some prominence, but his commitment to maintaining secrecy
and averting publicity was paramount. To avoid legal problems, Groves
agreed to a radiation monitoring system and an evacuation plan. No
protective measures were to be taken unless people suffered serious
injuries.[2]
[[link removed]]

On 7 May 1945, two months before the16 July test, Los Alamos
scientists staged a “dress rehearsal” by detonating 108 tons of
high explosives. The “100-ton test,” the largest explosion ever up
to that point, included an experiment for measuring the dispersal of
radioactive materials. Interlaced in the pile of high explosives was
flexible tubing containing a small amount of plutonium that had been
dissolved in chemicals. According to a later evaluation by Los Alamos
medical expert Louis Hempelmann, the risks were “slight” that the
dispersed plutonium could have adverse consequences, but this was the
first time that an explosion had spread plutonium.

Six days before the Trinity test, Los Alamos laboratory director J.
Robert Oppenheimer approved a recommendation that evacuation would
take place if the total amount of radiation absorbed by people living
in the area was in the range of 60-100 roentgen, some 50 times the
daily limit of 0.1 r. The focus of the monitoring was external
radiation, not the risk that people might inhale or ingest radioactive
material.[3]
[[link removed]] When
the test occurred, a U.S. Army detachment was ready with tents, food
and water supplies, stoves, and vehicles to evacuate several hundred
nearby people. Contingency planning included a press release
justifying evacuation: the hazard caused by “gas shells” in an
exploded ammunition dump. [See Document 11]

When the Trinity test occurred early in the morning of 16 July 1945,
it created a fireball whose temperature reached 8430 kelvin, or 14,710
F, hotter than the sun’s surface temperature (5778 K). Enrico Fermi
estimated that the explosive yield was 10 kilotons (TNT equivalent),
but that was incorrect by a factor of 2 and Groves later reported that
the yield was between 15 and 20 kilotons. In recent years, the
Department of Energy’s official estimate became 21 kilotons,
although a recent unofficial assessment postulates 24.8 kilotons.
Whatever the exact yield was, the explosion spewed dust and other
particles, including unfissioned plutonium, into the air and the
fallout spread northeast of Ground Zero.[4]
[[link removed]]

After the test occurred there were worrisome moments. On 16 July 1945,
radiation monitor Arthur Breslow wrote that there was the “danger of
an immediate evacuation and the [radiation] count was rising
rapidly.” [Document 12] He decided otherwise, and the consensus was
that radiation levels were not high enough to necessitate evacuation.
The special detachment was disbanded. All the same, a few days after
the test, Dr. Stafford Warren wrote to General Groves that “the dust
outfall from the various portions of the cloud was potentially a very
serious hazard over a band almost 30 miles wide extending almost 90
miles northeast of the site.” [Document 13]

Warren and others discovered that pre-test organizers had overlooked
nearby people who were at risk of over-exposure. Notably, the Ratliff
family, grandparents and their grandson, lived near a “Hot Canyon”
where radiation levels were high. Los Alamos medical staffers would
visit this downwinder family and a few others during the months that
followed the test and quietly checked on them. They concluded that
they were healthy, although cattle and other farm animals in the area,
including the Chupadera Mesa, had been exposed to fallout and
experienced burns on their skin because they had been out in the open.
The cattle would be the subject of clinical studies. [See Document 17]
Unnoticed, however, was that other downwinders, including young girls
at nearby camp, had also been exposed to dangerous levels of fallout.

Six weeks after the test, Victor Weisskopf and other radiation experts
corroborated Warren’s findings about the scope of fallout exposure.
They found a “swath of fairly high radioactivity on the ground
covering an area of about 100 miles long by 30 miles wide” [See
Document 15]. In a likely reference to the Ratliffs, they reported
that, “One ranch house east of Bingham received an initial radiation
intensity calculated to be 7 r/hr [roentgen per hour],” although the
intensities reached “tolerance” within a month. Moreover, after
the test, “gamma radiation was found in measurable but very low
intensities in Santa Fe, Las Vegas, Raton and even in Trinidad,
Colorado (260 miles from zero point).” The report concluded that the
radiation levels near the ranch house and elsewhere were not high
enough to be dangerous.

Fallout Studies

The fact that the Trinity test site itself was an enduring hot spot
and that the long-term biological effects of extensive “low grade”
radioactivity were unknown made health experts and policymakers
interested in supporting systematic research. Dr. Joseph Hamilton
[[link removed]],
then with the Berkeley Radiation Laboratory, saw two justifications
for further work. One was a potential legal question: the
“immediately practical questions” relating to the “possibilities
of biological injury to flora and fauna of the area and to man so as
to provide whatever data may be necessary to meet any medical legal
considerations which may arise.” Hamilton saw another purpose as
“more important” because of its broad military implications. That
involved the “accumulation and analysis of sufficient data [to] make
possible the prediction of the various chains of events which may take
place following the contamination of large land areas with the release
of fission products” whether by accident or military action. [See
Document 18]

To foster such research, Hamilton sent a proposal to Stafford Warren,
then Dean of UCLA’s Medical School. Three years after Trinity, with
funding from the Atomic Energy Commission, the newly-created Atomic
Energy Project at UCLA began a research effort to measure and evaluate
the scope and impact of the Trinity fallout. The Atomic Energy
Commission underwrote the “Alamogordo” research, which produced a
number of studies during the late 1940s and the 1950s. The studies had
limited circulation and are obscure to this day, although historian
Janet Farrell Brodie has shed light on them in her publications.[5]
[[link removed]] Today’s
compilation includes several of the UCLA reports, copies of which have
become difficult to secure due to recent policy changes by the
Department of Energy (see sidebar). The reports are highly technical,
but some of their conclusions are clear enough and readers with
scientific aptitudes and interests may find them useful for further
study.

The project director at UCLA, Dr. Albert W. Bellamy, was concerned
about possible hazards from “wind-blown dust that is in the air,
which is of frequent occurrence... especially as regards alpha
[[link removed]] emitters,”
which in the aggregate could “in time induce lung tumors in mice.”
But he believed that more data was necessary. Detecting alpha
radiation was an understood method of discovering plutonium in the
human body, but the technology in use at the time was imprecise at
best. While plutonium was a known toxin and understood to accumulate
in bones, its impact on humans was far from understood.

Published in 1949, the first UCLA Alamogordo study discussed a 1948
survey of a 1,130 square mile area extending northeast from the
Trinity site, the “swathe” of land discussed in the September 1945
Los Alamos report. The detonation area itself had levels of
radioactivity that “create a strong presumption of hazard to living
things that remain continuously in this area.” Otherwise, “the
amount of radioactive fission product to be found in any one place
throughout this area are relatively small.” The exception was the
Chupadera Mesa, 28 miles northeast of Ground Zero, where “enough
radioactive material [had] settled out … to produce superficial skin
‘burns’ on cattle grazing there.”

The report found that “the greatest concentration of radioactive
fission products are not great enough anywhere in the contaminated
region and especially outside the Crater Area to present a significant
immediate hazard to man or his domestic animals from total body
exposure to beta gamma contamination.” As “gratifying” as that
conclusion was, the authors left open the possibility of long-term
health risks. It “would be rash to conclude … that no hazards
associated with products of the bomb detonation exist in this area,
the harmful effects of which may not appear for a number of years.”

Like the 1948 survey, the reports that followed raised questions that
it could not answer. The report from early 1951 discussed findings for
the area “along the line of Fall-out for at least a distance of
eighty-five miles from the Fenced Area.” There the research team
found plutonium in soil and plants and “Alpha emitters, presumably
plutonium … in airborne material from the Crater Region and the
--Chupadera Mesa.” The scientists suggested that the “air-borne
material ... which because of its particle size and level of alpha
activity appear[ed] _at this time_, to be of greatest concern.” Yet
the “biological significance” of that and other data could not be
evaluated: it was not “possible under the present circumstances ...
to assess the potential hazard of plutonium found to the people and
cattle living” on the Mesa.

Another UCLA report from 1951 was also unsettling. For example, the
“fission product contamination of the Chupadera Mesa is relatively
greater now than in the past.” While the researchers found “no
hazard from external total body exposure to penetrating ionizing
radiation (gamma rays)” outside of the restricted area at Ground
Zero, they did not “assume at this point that that no hazard exists
… from the widespread fission product contamination.” They
reported that there are “many potential long term insidious hazards
from the present low level contamination which is the focal point of
these studies.” Evidence from the annual biological surveys was
“beginning to accumulate … that such hazards exist.”

A UCLA report from 1957 provided little comfort that radioactive
contamination had dissipated. Drawing on new data, researchers found
that that “the area originally contaminated by fall-out from the
Trinity detonation was greater than the 1,100 square miles estimated
by the 1948 survey” (although an updated square mile estimate was
not provided). The researchers found plutonium “in amounts up to
0.007 micrograms per square foot of soil, one-half inch deep, at a
distance of 88 miles northeast of the site of detonation,” with even
more, l07 micrograms per square foot, on the Chupadera Mesa. Thus,
there had been “no appreciable decrease in plutonium content of the
soils … due to erosional factors.”

That radioactive contamination persisted in the Trinity area and in
New Mexico was detailed in other reports. None of the UCLA studies
pointed to a specific public health impact from the contamination.
Even though most of the reports were unclassified, they were closely
held and unavailable for many years. By contrast, the Center for
Disease Control published a major study in 2010, the Los Alamos
Historical Document Retrieval and Assessment, based on wide ranging
research in the Los Alamos Laboratory archives, which sought to
determine the impact on New Mexico of the Laboratory’s radioactive
releases, including the Trinity test.[6]
[[link removed]]

The LAHDRA report provided much information, including the startling
finding that the Trinity test produced radiation “exposure rates in
public areas [that] were measured at levels 10,000-times higher than
currently allowed” (p. 22-3). Nevertheless, it refrained from
drawing conclusions about the health impact. Even though “internal
radiation doses could have posed significant health risks for
individuals exposed after the blast … [too] much remained
undetermined about exposures from the Trinity test to put the event in
perspective as a source of public radiation exposure or defensibly
address the extent to which people were harmed.” (p. 10-50).

To fill the gaps in the LAHDRA report, the National Cancer Institute
assessed the health impact of the Trinity radiation, eventually
producing studies estimating radiation doses and projecting cancer
risks from fission products. A recent study summarized the NCI’s
findings: significant exposures to fallout “were limited to five
counties (Guadalupe, Lincoln, San Miguel, Socorro, and Torrance), with
those counties “projected to account for more than 70% of the excess
cancer cases.” Specifically because thyroid glands concentrate
radioidine (one of the radionuclides created by the detonation),
“thyroid cancer was estimated to be the most common cancer type that
could possibly be attributed to fallout exposure.” The
“attributable fraction of Thyroid cancers among the 1945 population
in New Mexico was 9.7%” compared to 0.3% for all types of cancer
generally. How other health experts have evaluated these findings has
not yet surfaced.[7]
[[link removed]]

The findings about excess thyroid cancers has supported apprehension
about Trinity among New Mexican downwinders, who have undertaken
long-standing efforts to seek federal compensation.[8]
[[link removed]] When
Congress passed the 1990 Radiation Exposure and Compensation Act
(RECA) it excluded populations in New Mexico despite their exposure to
the test’s radiation.[9]
[[link removed]] This
exclusion was remarkable when one considers the extent of radioactive
contamination caused by the Trinity fallout. A recent study
[[link removed]] underlines that point by finding
that 28 of 33 New Mexican counties, including federally recognized
tribal areas, experienced levels of radionuclide deposition that were
higher than counties elsewhere that already had RECA coverage. Socorro
Country, where the Trinity test occurred, had the 5th highest
deposition per county of all counties in the U.S. To make up for the
discrepancy, the U.S. Senate has passed legislation
[[link removed]] that
covers counties in New Mexico and other U.S. areas, but the opposition
of Speaker Mike Johnson (R-LA) has prevented consideration by the
House of Representatives.

NOTE: Thanks to Janet Farrell Brodie, professor emeritus, History
Claremont Graduate University, for providing document copies and
information about her research; to archivists at the University of New
Mexico’s Center for Southwestern Research for documents from the
Ferenc Szasz papers and permission to use them; to Peter Kuran, for
sharing footage of the “100-ton” test; to archivists at Los Alamos
Laboratory for copies of films and photographs; and to John Fratis
Tobin, Pennsylvania State University, for research assistance.

THE DOCUMENTS

I. The 100-Ton Test

[ebb 866 doc 1]

Document 1

L. ANDERSON, _RADIOACTIVITY MEASUREMENTS AT THE 100-TON TRIAL_, LA
REPORT 282, 25 MAY 1945, SECRET
[[link removed]]

May 25, 1945

Source

Los Alamos National Laboratory Website

To prepare for the Trinity Test, especially to help scientists and
technicians calibrate and prepare measuring instruments and
communications systems, Kenneth Bainbridge supervised a test on 7 May
1945 that exploded 108 tons of high explosives stacked in a tower at
the Alamogordo site. Because there had been no previous tests with
massive blast effects, Bainbridge saw it as a necessary “dress
rehearsal.”[10]
[[link removed]]

With Los Alamos health and safety experts already concerned about
fallout that the Trinity test would produce, a major purpose of the
100-ton test was to estimate the dispersal of fission products. To
make that possible, the scientists obtained from the Hanford
reprocessing plant a “slug” of plutonium that they dissolved in
chemicals and then placed in flexible tubing that technicians strung
through the stack of high explosives [See Film 1].

In his report to General Groves on the test, Richard T. Tolman
observed that it produced a “highly luminous sphere, which then
spread out into an oval form,” that was followed by the “ascent of
the expected hot column which mushroomed out at a height of some 15000
ft.”[11]
[[link removed]] Herbert
Anderson
[[link removed]], one
of the scientists who worked on the 100-ton test, later reported that
of the 9,500 cubic feet of earth displaced and loosened by the blast,
40 percent was dispersed outside the crater. Pulverized earth carried
most of the radioactivity with the finest particles being three times
more radioactive than the larger ones. As Brodie has observed, “This
should have raised alarms given the serious windstorms that swept
through the New Mexico plains, but apparently did not.”[12]
[[link removed]]

[ebb 866 doc 2]

Document 2

R.L. ANDERSON, _100-TON TEST: RADIOACTIVITY ABOVE THE CRATER AFTER 41
DAYS_, LA REPORT 282A, 22 JUNE 1945, SECRET
[[link removed]]

Jun 22, 1945

Source

Los Alamos National Laboratory Website

Anderson reported on the latest survey of radiation above the crater
41 days after the test. The purpose was to determine the “permanence
of the [radio]active deposit exclusive of the effect of the
radioactive decay.” There was substantially less radioactive
material “due to the effect of the wind in dispersing the ...
material outside the region in which there was measurable activity.”

[ebb 866 doc 3]

Document 3

LOUIS HEMPELMANN, “HAZARDS OF THE 100-TON TEST AT TRINITY,” 18 MAY
1946, SECRET (EXCERPT FROM L. H. HEMPELMANN, _PREPARATION AND
OPERATIONAL PLAN OF MEDICAL GROUP (TR-7) FOR NUCLEAR EXPLOSION 16 JULY
1945_,” SECRET, 13 JUNE 1947
[[link removed]]

May 18, 1946

Source

Federation of American Scientists
[[link removed]]

Dr. Louis Hempelmann, the director of medical and health affairs at
Los Alamos, found that there were “slight” risks from the test’s
dispersal of radioactive products. The explosion produced a cloud that
lofted 98 percent of the material rising to a height of 13,000 to
15,000 feet. Project meteorologists concluded that thermal air
currents contributed to the cloud’s “rapid dispersion.”

II. Preparing for the Trinity Test and Discussion of Possible Risks

[ebb 866 doc 4]

Document 4

LOUIS HEMPELMANN AND RICHARD WATTS, “HAZARDS OF TRINITY
EXPERIMENT,” 12 APRIL 1945, SECRET
[[link removed]]

Apr 12, 1945

Source

Department of Energy [DOE] Open-Net

With the first atomic test approaching, doctors and scientists at Los
Alamos began looking closely at precautions and radiation safety
measures. Louis Hempelmann prepared the first part of a memorandum
that described the effects that could pose dangers, such as blast,
radiation, and radioactive materials. Discussing what later became
known as fallout, Hempelmann wrote that the “worst possible hazard
from radioactive dust would seem to be the one in which the explosion
is of sufficient energy to only get the material in the form of a
cloud of fine dust.” If the particles fell on a nearby shelter, it
would be “dangerous … to breathe for more than 6 minutes.”

To make it possible for real-time measurements of beta and gamma
radiation and airborne fission products and to protect staff from
radiation, the second part of the memorandum, prepared by electronics
specialist Richard Watts, recommended deploying measuring instruments
at shelters and mobile units and the organizational structure needed
for this work.

[ebb 866 doc 5]

Document 5

BAINBRIDGE TO CAPTAIN T. O. JONES, “LEGAL ASPECTS OF TR TESTS,” 2
MAY 1945, SECRET
[[link removed]]

May 2, 1945

Source

DOE Open-Net

Kenneth Bainbridge, the chief planner for the Trinity test, likely saw
the Hempelman-Watts memorandum and spoke with General Groves about the
“medical legal” problem. Point by point, Bainbridge reviewed the
nearby human settlements and installations that radiation could
affect, including ranches, towns, and military personnel. In the event
that evacuation was necessary, Groves believed that officers would
have to accompany military police along with some physicists who would
take measurements. Groves also wanted to involve experts on earth
shock, blast effects, and the spread of radioactivity, all of whom
could be consulted. Owing to the risk of contamination by various
fission products, “certain legal problems will arise because some of
this land is homestead entry land, some is vacant land, and some is
state grazing land.”

[ebb 866 doc 6]

Document 6

HIRSCHFELDER AND JOHN MAGEE TO K. O. BAINBRIDGE, “DANGER FROM ACTIVE
MATERIAL FALLING FROM CLOUD – DESIRABILITY OF BONDING SOIL NEAR ZERO
WITH CONCRETE AND OIL,” 16 JUNE 1945, SECRET
[[link removed]]

Jun 16, 1945

Source

DOE Open-Net

Two Los Alamos scientists, John Magee
[[link removed](chemist)], a physical
chemist, and Joseph Hirschfelder
[[link removed]], a physicist
working in the Ordnance and Engineering Division, reinforced
Hempelmann’s message about likely hazards. Perhaps influenced by
Anderson’s finding about fine particles, Hirschfelder and Magee
cited the “definite danger of dust containing active material and
fission products falling on towns near Trinity and necessitating their
evacuation.”[13]
[[link removed]] Looking
at what could happen to people in the area, they suggested that an
individual could receive “approximately 22 R” in the hours after
the explosion. That was over 100 times higher than the then-current
official safety standard of 0.1 R.[14]
[[link removed]] To
mitigate the risk and curtail the spread of radioactive dust, they
proposed deploying crushed rock, concrete slurry and a film of oil at
the test site.

Hirschfelder and Magee experienced pushback very quickly—no one
wanted to credit their forecast, but they were prescient. Hirschfelder
later recalled that “very few people believed us when we predicted
radiation fallout from the atom bomb,” observing that the government
“acted very cavalierly toward the danger.”[15]
[[link removed]]

[ebb 866 doc 7]

Document 7

“MEDICAL HAZARDS OF TR # 2,” CIRCA 19 JUNE 1945, NO CLASSIFICATION
MARKINGS, EXCISED COPY
[[link removed]]

Jun 20, 1945

Source

DOE Open-Net

Captain James F. Nolan, Hempelmann’s deputy, prepared a report on
plans for monitoring radiation and the evacuation of nearby towns in
the event of an emergency. The premise was that no individual should
“receive more than five (5) r[oentgen] at one exposure.” Five was
an arbitrary figure and possibly dangerous in itself, as it was fifty
times higher than the prevailing safety standard.[16]
[[link removed]]

[ebb 866 doc 8]

Document 8

LANSING LAMONT INTERVIEW WITH JAMES FINDLAY [SIC] NOLAN, N.D.
[[link removed]]

no date

Source

Harry S. Truman Presidential Library, Lansing Lamont Papers, box 1,
Notes (Rough Research)

Requiring high-level approval for the safety plan, Los Alamos Medical
Group Deputy Director Nolan flew to “Site X” to meet with General
Groves on 19 July. “Site X” was the gaseous diffusion plant in
Clinton, TN (later known as Oak Ridge Laboratory), that produced the
highly-enriched uranium used in the “Little Boy” weapon. Years
later, Nolan recounted the difficult encounter to Lansing Lamont
(author of _Day of Trinity_). After waiting outside Groves’ office,
Nolan was ushered in. According to his account, after Groves read the
report, he “sniffed,” saying, “What's the matter with you, are
you a Hearst propagandist?” Nolan recounted that Groves “seemed
genuinely sore at [him] for bringing up the prospects of radioactive
contamination.” It later took the intervention of the higher-level
official Stafford Warren to convince Groves to approve the plan.[17]
[[link removed]] What
upset Groves was the prospect that evacuations could put MED security
at risk by attracting the attention of the media, although he may also
have been unsettled by the subject of bomb-connected radiation.

[ebb 866 doc 9]

Document 9

L.H. HEMPELMANN AND J.F. NOLAN TO K.T. BAINBRIDGE, “DANGER TO
PERSONNEL IN NEARBY TOWNS EXPOSED TO ACTIVE MATERIAL FALLING FROM
CLOUD,” 22 JUNE 1945, SECRET
[[link removed]]

Jun 22, 1945

Source

DOE Open-Net

A few days after meeting with Groves, Nolan and Hempelmann jointly
responded to the Hirschfelder/Magee memorandum (Document 6). Their
response has been controversial, with some historians believing that
it downplayed the radiation danger while others took the opposite
view. Compared to Hirschfelder and Magee, Nolan and Hempelmann saw
“less likelihood of serious damage to individuals in neighboring
towns,” but they allowed for the possibility of “serious”
hazards and the necessity for evacuation. Certainly, the efforts to
get Groves to approve a monitoring system suggested recognition of the
need for safeguards, but it is possible that the higher-level
downplaying of radiation dangers encouraged Nolan and Hempelmann to
find a middle position. Informing the decisions to monitor
Trinity-produced radiation was the need to gather evidence in the
event of future legal claims against the government.[18]
[[link removed]]

[ebb 866 doc 10]

Document 10

“CONFERENCE ABOUT CONTAMINATION OF COUNTRYSIDE NEAR TRINITY WITH
RADIOACTIVE MATERIALS,” 10 JULY 1945, ANNOTATED DRAFT, NO
CLASSIFICATION MARKINGS
[[link removed]]

Jul 10, 1945

Source

DOE Open-Net

A week before the test, Los Alamos lab director Robert Oppenheimer met
with radiation experts, including Stafford Warren, James F. Nolan,
Louis Hempelmann, and Victor Weisskopf. After reviewing the mechanisms
that produced fallout and its dispersal, they heard a briefing on
optimum weather conditions: the wind velocity should not be too “too
high” and a wind to the south would be best because there were no
nearby towns and the mountains that would block the spread. A
tolerance dose (maximum level) of up to a 100 roentgen was acceptable
unless there was further exposure. If the total “integral dose”
(total amount absorbed by the body) was in the 60-100 roentgen range,
however, evacuations would then be necessary.

III. The Test and its Immediate Consequences

[ebb 866 doc 11]

Document 11

MEMORANDUM BY MAJOR T. O. PALMER, DETACHMENT COMMANDER, ARMY SERVICE
FORCES, UNITED STATES ENGINEER OFFICE, “EVACUATION DETACHMENT AT
TRINITY,” N.D., [CIRCA 17 JULY 1945], SECRET (EXCERPT FROM L. H.
HEMPELMANN, “PREPARATION AND OPERATIONAL PLAN OF MEDICAL GROUP
(TR-7) FOR NUCLEAR EXPLOSION 16 JULY 1945,” LOS ALAMOS LABORATORY,
13 JUNE 1947)
[[link removed]]

Jul 17, 1945

Source

Federation of American Scientists
[[link removed]]

The Trinity test planners prepared for the evacuation of any
endangered civilians by positioning a small force of 140 enlistees,
four officers, and 140 vehicles, equipped with tents, drinking water,
rations, coffee, sugar, and milk, among other supplies. The shelter
and supplies were estimated to be enough for 450 people for two days.
The detachment’s headquarters were set up near Bingham, “the
center of the area in the most immediate danger.” Two press releases
had been prepared: one concerning the explosion of an ammunition dump,
the other explaining the presence of “gas shells” at the
ammunition dump that necessitated evacuation for 24 hours to protect
people “from the gas and degree of contamination.”

Radiation monitors worked from the base near Bingham and reported to
Joseph Hoffman and Joseph Hirschfelder. On 16 July at about 1 p.m.,
when any possibility of “serious contamination” had passed,
Hoffman released the special detachment from further duty.

[ebb 866 doc 12]

Document 12

ARTHUR BRESLOW TO J.G. HOFFMAN, “RADIATION MONITORING AND
ITINERARY,” N.D.  [CIRCA 17 JULY 1945],  EXCERPT FROM TYPED
MEMORANDUM WITH COPY OF HAND-WRITTEN NOTES ATTACHED, SECRET
[[link removed]]

Jul 17, 1945

Source

for partial copy of Breslow memorandum: University of New Mexico
Libraries, Center for Southwestern Research, Ferenc Morton Szasz
papers, box 8, folder 38; source for handwritten notes: DOE OpenNet

Los Alamos staffer Arthur Breslow was in the group monitoring
radioactivity after the test. After taking readings from “falling
particles from the cloud which had passed overhead,” a radio failure
prevented him from communicating the readings. Leaving his crew
behind, he drove quickly to find another radio and saw that the valley
in front of him was covered “with a strata of sand-like dust”
forming clouds.  Discovering that he had not taken his respirator, he
closed the windows and used a slice of bread as a filter! Once he had
reached a radio close to Bingham, Breslow learned that “there was
danger of an immediate evacuation and the count was rising rapidly.”
He drove back to warn his crew but by then the readings were lower and
no evacuation decision was made.[19]
[[link removed]]

[ebb 866 doc 13]

Document 13

STAFFORD WARREN TO MAJOR GENERAL GROVES, “REPORT ON TEST II AT
TRINITY 16 JULY 1945,” 21 JULY 1945, TOP SECRET, WITH TABLES
ATTACHED
[[link removed]]

Jul 21, 1945

Source

National Archives, Record Group 77, Records of the Office of the Chief
of Engineers, Manhattan Engineer District, Top Secret Manhattan
Project Files, folder 4, “Trinity Test” (Microfilm Roll 1)

Stafford Warren’s report dovetailed with Breslow’s account because
of his serious concern about the radioactive debris: “the dust
outfall from the various portions of the cloud was potentially a very
serious hazard over a band almost 30 miles wide extending almost 90
miles northeast of the site.” Warren was close to using the term
“fallout,” but “outfall” conveyed the idea. He also observed
that there was still “a tremendous amount of radioactive dust
floating in the air.” These problems informed his recommendation
that any future tests should take place not in Alamogordo but in a
region “with a radius of at least 150 miles without population.”

The cloud column mass and top reached a phenomenal height, variously
estimated as 50,000 to 70,000 feet,” which towered over the
northeast corner of the site for several hours.” Referring to a
“deserted canyon” 20 miles northeast of Zer, Warren reported that
“intensities ... were high enough to cause serious physiological
effects.” He further reported to Groves that it was his opinion
“that lethal or severe casualties would occur to exposed personnel
up to two miles from a variety or combination of causes, i.e., blast,
heat, ultraviolet and missiles.” Those were some of the effects that
would be demonstrated at Hiroshima and Nagasaki, although Warren did
not mention radioactivity as a lethal factor and perhaps confused it
with ultraviolet.

Attached to Warren’s memorandum were diagrams showing the “path of
the cloud,” information about the “hot canyon” and the nearby
“house with family” [See Document 16], and the cover note to a map
showing “isodose curves” indicating the spread of radioactivity.

On 22 July 1945, Warren wrote privately to Nolan, giving him far more
alarming impressions: radiation monitors “found radiation at levels
as high as thirty to forty roentgens ‘near a lot of houses’ and,
in ‘one hot canyon’ northeast of Bingham, radiation ‘totaling
230r.’” Warren further wrote: “Boy what a narrow escape. If we
had laid it down in a steady wind as planned when you left we would
have had a high mortality!! It was terrific.”[20]
[[link removed]]

[ebb 866 doc 14]

Document 14

ENTRY FROM GENERAL GROVES DIARY, 27 JULY 1945
[[link removed]]

Jul 27, 1945

Source

National Archives, Donated Records of General Leslie R. Groves,
Visitations and Telephone Call Diaries, box 3

The information in Warren’s report may have prompted Groves to call
Warren and ask him about a “certain family there.” Groves received
a follow-up call informing him that Hymer Friedell’s
[[link removed]] “boys
had made some further observations and are “concerned about one
family [no doubt the Ratliffs] to the extent that they want to get in
touch with [them] to see how they feel” [See Documents 15 and 16].
While Friedell’s group wanted advice on the “legal end,” Groves
said that “there was nothing I could do about it” and that they
should confer with Warren. All that was done was to keep an eye on the
Ratliff family.

[ebb 866 doc 15]

Document 15

INTER-OFFICE MEMORANDUM BY V. WEISSKOPF, J. HOFFMAN, P. AEBERSOLD, AND
L. HEMPELMANN TO G. KISTIAKOWSKY, “MEASUREMENT OF BLAST, RADIATION,
HEAT AND LIGHT AND RADIOACTIVITY AT TRINITY,” 5 SEPTEMBER 1945,
SECRET
[[link removed]]

Sep 5, 1945

Source

DOE Open-Net

After providing measurements for the test itself, Victor Weisskopf and
his colleagues described the “extremely high” radioactivity in and
around the crater but which “decreased rapidly during the first few
days.” The final section discussed the fallout on northeastern New
Mexico, for which there was a “swath of fairly high radioactivity on
the ground covering an area of about 100 miles long by 30 miles
wide.” In what was likely a reference to the Ratliff family [See
Document 16], “One ranch house east of Bingham received an initial
radiation intensity calculated to be 7 r/hr [roentgen per hour].”
Moreover, “gamma radiation was found in measurable but very low
intensities in Santa Fe, Los Vegas, Raton and even in Trinidad,
Colorado (260 miles from zero point).”

[ebb 866 doc 16]

Document 16

JOSEPH G. HOFFMAN, “NUCLEAR EXPLOSION 16 JULY 1945: HEALTH PHYSICS
REPORT ON RADIOACTIVE CONTAMINATION THROUGHOUT NEW MEXICO FOLLOWING
THE NUCLEAR EXPLOSION,” OFFICIAL USE ONLY, LOS ALAMOS SCIENTIFIC
LABORATORY, 20 FEBRUARY 1947, OFFICIAL USE ONLY, EXCISED COPY
[[link removed]]

Feb 20, 1947

Source

DOE Open-Net

Joseph Hoffman
[[link removed]],
who directed the radiation monitoring activities for the area beyond
the Trinity site, produced a detailed account of the monitoring
immediately at the time of the July 1945 test. According to Hoffman,
“one half of all the [radio]activity available was precipitated in
the two weeks after the explosion” and 90 percent of it was in New
Mexico. As Brodie noted, Hoffman acknowledged “that a localized
‘hot spot’ might have occurred, none was found, and the actual
contamination indicated a uniform distribution at a concentration
which is considered not to constitute a health hazard.” No
monitoring occurred near the Mescalero Apache Reservation or
at Ruidoso
[[link removed]],
the location of a girls camp that “received significant fallout.”
With respect to the Apache reservation, Brodie suggests that the test
planners chose a day when the “most likely wind direction blew to
the north,” thus avoiding the area around that territory.

Almost all of the names of the radiation monitors and other officials
mentioned in this report were excised for “privacy reasons.” For
example, Arthur Breslow’s name was excised (and Hoffman did not
mention his vivid account). Given that the excisions were probably
made decades after Hoffman produced this report, they were likely a
misuse of the Privacy Act; the individuals mentioned were probably
long retired from government service. The National Security Archive
has requested an unredacted copy of the report.

[ebb 866 doc 17]

Document 17

LOS ALAMOS SCIENTIFIC LABORATORY OF THE UNIVERSITY OF CALIFORNIA, L.
H. HEMPELMANN, COMPILER, “NUCLEAR EXPLOSION 16 JULY 1945: HEALTH
PHYSICS REPORT ON RADIOACTIVE CONTAMINATION THROUGHOUT NEW MEXICO
FOLLOWING THE NUCLEAR EXPLOSION, PART B: BIOLOGICAL EFFECTS,” 3 JULY
1947, OFFICIAL USE ONLY
[[link removed]]

Jul 3, 1947

Source

Federation of American Scientists Website
[[link removed]]

During the weeks and months after Trinity, Dr. Louis Hempelmann and
Los Alamos colleagues visited people who lived near the test site and
collected data on beta burns on dogs and ranch cattle. In July 1947,
Los Alamos published a compilation of the reports and memoranda that
Hempelmann had prepared after the test.

One downwinder family that Hempelmann and others visited several times
were the Ratliffs, a pair of grandparents and their grandson, who had
been completely unnoticed during the pre-test surveys. They lived near
the “Hot Canyon” where fallout levels had been high. The grandson
was at school on 16 July so he had less exposure during those hours.
The grandparents did not report anything unusual about that day,
although during his initial visit, Hempelmann wrote that there was
“rain in this area on the night after the shot: this means that some
of the [radio]activity was carried into their drinking water and may
have been drunk on the following day and thereafter.” [Page 7]
During a subsequent visit, on 11 November, Mr. Ratliff told Hempelmann
something that he had not mentioned before: “an interesting story of
the appearance of the ground immediately after the shot.” The
“ground and fence posts had the appearance of being covered with
light snow, or of being ‘frosted’ for several days after the
shot” [Page 69].

The Los Alamos staffers took samples of the drinking water but
apparently none of them mentioned possible health risks to the
Ratliffs or others. According to Hempelmann’s calculations during
the two weeks after Trinity, the Ratliffs received an estimated 47.0
roentgens of gamma radiation when the “allowable limit” was 1.4
roentgens (Page 9). In any event, during the weeks after the test,
Hempelmann reported that the Ratliffs appeared to be in “excellent
health.” Other nearby families who experienced the fallout were
completely overlooked.[21]
[[link removed]] Years
later, Hempelmann observed, “a few people were probably overexposed,
but they couldn’t prove it and we couldn’t prove it. So we just
assumed we got away with it.”[22]
[[link removed]]

Much of this compilation consists of reports, some highly clinical,
focusing on the fallout exposure of farm animals, mostly cattle, but
also cats and dogs on the Ratliff ranch and elsewhere. With respect to
cattle, Hempelmann and others reported lesions on the skin and hair
loss, although the cattle appeared normal in other respects. Data
collected by the Army indicated that up to 600 cattle in the Trinity
area “showed signs of beta rays damage” [Page III-8, after page
69]. The Army purchased 75 of the most affected cattle, with 17 going
to Los Alamos and 61 shipped to “Site X.” At Oak Ridge, they
experienced various health problems, including skin cancer, with the
last surviving member, “Granny,” living until she was euthanized
in 1964.[23]
[[link removed]]

IV. Post-Test Studies and Research

[ebb 866 doc 18]

Document 18

JOSEPH G. HAMILTON, M.D., RADIATION LABORATORY, UNIVERSITY OF
CALIFORNIA, TO DEAN STAFFORD WARREN, 20 NOVEMBER 1947
[[link removed]]

Nov 20, 1947

Source

Copy courtesy of Janet Farrell Brodie

Medical doctor and radiation expert Joseph Hamilton
[[link removed]] was
participating in human radiation experiments
[[link removed]] by
the time he presented Stafford Warren (who had become a dean at UCLA)
with a proposal for long-term studies of the impact on New Mexico of
the Trinity explosion. After providing some “sketchy information”
concerning the presence of “fission product activity” in a 100
square mile area adjacent to the test site, he suggested a research
program divided into two areas.

One area was the “immediately practical questions which relate to
the possibilities of biological injury to flora and fauna of the area
and to man so as to provide whatever data may be necessary to meet any
medical legal considerations which may arise.” The other and “more
important” area of research had military implications. It involved
the “accumulation and analysis of sufficient data which make
possible the prediction of the various chains of events which may take
place following the contamination of large land areas with the release
of fission products” whether by accident or military action.

From Hamilton’s perspective, the long-range need was to “secure as
wide a fund as possible of general information about the contaminated
region and any adjacent area which may possess a comparable degree of
radioactivity.” Thus, major items for detailed study would be the
distribution of fission products in plant life and livestock as well
as studies of soil samples. In the meantime, the U.S. “should not
open any new areas for grazing until two points are settled, first,
the degree of uptake of radioactivity by the livestock, and second,
adequate monitoring of all areas which may be contaminated by fission
product and plutonium activity.”

Among Hamilton’s conclusions was that the “basic knowledge gained
from such studies is indispensable to an evaluation of what the future
may bring and the steps which may be taken to meet these problems.”
Warren accepted Hamilton’s proposal, and within months the AEC was
funding studies at UCLA of the long-term impact of the Trinity
test.[24]
[[link removed]]

[ebb 866 doc 19]

Document 19

ALBERT W. BELLAMY, CHIEF, ALAMOGORDO SECTION, UNIVERSITY OF
CALIFORNIA, ATOMIC ENERGY PROJECT, TO JAMES H. JENSEN, ASSISTANT
DIRECTOR OF BIOLOGY AND MEDICINE, ATOMIC ENERGY COMMISSION, 6 OCTOBER
1948, CONFIDENTIAL, ANNOTATED COPY
[[link removed]]

Oct 6, 1948

Source

University of New Mexico, Center for Southwest Research, Ferenc Szasz
Papers, box 8, folder 48

Albert W. Bellamy
[[link removed]],
a professor of zoology and biophysics at UCLA, became the director of
the Atomic Energy Project’s research on the effects of the Trinity
Test.  Having attended a conference on the radiation effects at
Socorro, NM, he sent a senior AEC official some of the “more
significant impressions and conclusions” concerning the area
contaminated by the test. He did not see a “total body radiation”
hazard in the area “unless someone should chose to spend about two
days or more lying in the ground in the most active area.” There
were, however, possible hazards from “wind-blown dust that is in the
air, which is of frequent occurrence ... especially as regards alpha
[[link removed]] emitters,”
which in the aggregate could “in time induce lung tumors in mice.”
But more data was needed. He also mentioned “evidence that certain
plants will take certain elements from very low concentrations in the
soil and concentrate them in high degree.”

One of the conference’s conclusions was the need to “determine,
with a minimum of time and expense, whether or not biological hazards
still exist in the area.” That would involve a “bioassay” of
livestock that had grazed in the “active area” for over two years.
He suggested “bringing in about 20 head of young stuff from outside
the Socorro region” with one group to be “maintained in the most
active area on the Chupadera” and the other “in a nearby
uncontaminated area.” Also recommended was “greenhouse-laboratory
work on plants … to estimate the probability of long range
hazards.”

With respect to the trinitite
[[link removed]]—the soil that the
explosion turned into a glass-like substance—at the test site, the
conference discussed the “feasibility of preparing a release for the
Socorro paper to give the local population some idea of the dangers of
getting too familiar with the greenglass and beads.”

[ebb 866 doc 20]

Document 20

MINUTES, ADVISORY COMMITTEE ON BIOLOGY AND MEDICINE, TWELFTH MEETING
HELD AT HANFORD OPERATIONS OFFICE RICHLAND, WASHINGTON OCTOBER 8-9,
1948
[[link removed]]

Dec 31, 1969

Source

RMI Nuclear Justice Documents

Radioactive contamination at the test site continued to invite
discussion. During a meeting of the AEC’s Advisory Committee on
Biology and Medicine, James Herbert Jensen
[[link removed]],
chief of the AEC’s biology staff, discussed a recent visit to the
Trinity site. “The question whether the area should be fenced off as
a hazardous area was thoroughly discussed.” With the grasses showing
“a fairly high level of activity,” he proposed purchasing 10 head
of cattle to determine whether “anything of a detrimental nature
accumulated in these animals.” With respect to the trinitite found
on the test site, the Committee decided that “active measures should
be taken to remove this as a potential hazard.”

[ebb 866 doc 21]

Document 21

UNIVERSITY OF CALIFORNIA LOS ANGELES, ATOMIC ENERGY PROJECT, “THE
1948 RADIOLOGICAL AND BIOLOGICAL SURVEY OF AREAS IN NEW MEXICO
AFFECTED BY THE FIRST ATOMIC BOMB DETONATION,” UCLA-32, 17 NOVEMBER
1949, SECRET
[[link removed]]

Nov 17, 1949

Source

DOE Open-Net

This is the first report on Trinity radiation prepared by Albert
Bellamy’s Alamogordo Project at UCLA in keeping with the AEC’s
authorization to “conduct a systematic survey of the area ... to
estimate the probability that hazards now exist or may arise in the
future as a result of widespread low grade radioactivity.” The
territory in New Mexico surveyed was the area around Trinity, the Red
and Grey Hills Region, the Oscuro Mountains, the Chupadera Mesa, and
the Rolling Plains Region, an area comprising 1130 square miles.

According to the report, “all [radio]activities outside the Crater
are found in the upper two inches of soil,” and “spread by wind
and water, particularly in the Trinity Region.” A radiological
survey of 402 small animals “found that activity when present was
associated with the digestive tract,” with “no substantial
indication of tissue accumulation.” At the detonation point area
“radioactivity is still present to create a strong presumption of
hazard to living things that remain continuously in this area.” That
made it necessary to enclose 145 acres with a fence. Otherwise, “the
amount of radioactive fission product to be found in any one place
throughout this area are relatively small.”

On the Chupadera Mesa, a grazing area controlled mainly by four ranch
owners, “there is a larger amount of radioactivity than in any other
place except near the Crater”: “enough radioactive material …
settled out over this area to produce superficial skin ‘burns’ on
cattle grazing there.” Nevertheless, the report found that “the
greatest concentration of radioactive fission products are not great
enough anywhere in the contaminated region and especially outside the
Crater Area to present a significant immediate hazard to man or his
domestic animals from total body exposure to beta gamma
contamination.” That conclusion was “gratifying … but it would
be rash to conclude, in the absence of specific information, that no
hazards associated with products of the bomb detonation exist in this
area, the harmful effects of which may not appear for a number of
years.”

[ebb 866 doc 22]

Document 22

H. LARSEN ET AL., UNIVERSITY OF CALIFORNIA LOS ANGELES, SCHOOL OF
MEDICINE, ATOMIC ENERGY PROJECT, “ALPHA ACTIVITY DUE TO THE 1945
ATOMIC BOMB DETONATION AT TRINITY, ALAMOGORDO, NEW MEXICO --- AN
INTERIM REPORT,” UCLA-108, SUBMITTED 5 JANUARY 1951, NOTES AND
ANNOTATED EXCERPTS, UNCLASSIFIED
[[link removed]]

Jan 5, 1951

Source

University of New Mexico, Center for Southwest Research, Ferenc Szasz
Papers, box 7, folder 34

This study is listed on OpenNet as being in the NTA collection and the
editor has requested a PDF from the Department of Energy. Only the
excerpts collected by Ferenc Szasz
[[link removed]] and
his notes are available at present.

In this research update, the UCLA scientists reported that they had
found plutonium in soil and plants collected from various locations
“along the line of Fall-out for at least a distance of eighty-five
miles from the Fenced Area.” They also found “alpha
[[link removed]] emitters,
presumably plutonium, … in airborne material from the Crater Region
and the Chupadera Mesa.” While concentrations in the soil were
variable, the “maximum concentrations ... outside the Fenced Area
are found approximately twenty-eight miles from Zero in the downwind
trail of the Fall-out.” The scientists suggested that the
“air-borne material ... because of its particle size and level of
alpha activity appear[ed] _at this time_, to be of greatest
concern.”

The researchers studied rodents that had been collected 28 to 30 miles
from the Crater and found alpha activity in their bones, liver, muscle
and connective tissue. By contrast, they did not find alpha activity
in rodents that were collected in and near the Crater. With respect to
the data’s “biological significance,” they could not evaluate it
because it was not “possible under the present circumstances ... to
assess the potential hazard of plutonium found to the people and
cattle living on the Chupadera Mesa.” According to the report,
“this area is not suitable for the collection of field data on food
ordinarily consumed by humans and no good study has been possible with
cattle in the area.”

[ebb 866 doc 23]

Document 23

K.H. LARSON ET AL., “THE 1949 AND 1950 RADIOLOGICAL SOIL SURVEY OF
FISSION PRODUCT CONTAMINATION AND SOIL-PLANT INTERRELATIONSHIPS OF
AREAS IN NEW MEXICO AFFECTED BY THE FIRST ATOMIC BOMB DETONATION
(TRINITY),” UCLA-140, 12 JUNE 1951, CONFIDENTIAL, EXCERPTS
[[link removed]]

Jun 1, 1951

Source

University of New Mexico, Center for Southwest Research Szasz Papers,
Box 14, Folder 5, Field Reports of Trinity, 1951

Open-Net
[[link removed]] provides
details on this report, but like the previous UCLA study, DOE has yet
to provide a PDF. Based on 1949 and 1950 radiological surveys of soil
and plant life and their interrelations, this detailed report included
disquieting findings concerning the residual radioactivity of the
Trinity Fall-out. For example, “measurable amounts of radioactive
fission products ... still are present” in the Ratliff area (near
the “Hot Canyon”), the Chupadera Mesa, and “Area 21” (28 miles
northeast of Zero). On the Mesa, radioactive contamination was
“still concentrated in the upper one or two inches of soil,” while
“downward migration of the radioactive fission products may be
taking place.” Further, “the relatively greater uptake observed in
1950, compared to 1949, points out that as a potential biological
hazard the remaining … fission product contamination of the
Chupadera Mesa is relatively greater now than in the past.”

The researchers found “no hazard from external total body exposure
to penetrating ionizing radiation (gamma rays) exists any place
outside of the Fenced Area,” but they would not “assume at this
point that that no hazard exists outside of the Fenced area from the
widespread fission product contamination.” In addition, outside the
Fenced Area there are “many potential long term insidious hazards
from the present low level contamination which is the focal point of
these studies.” Evidence from the annual biological surveys was
“beginning to accumulate … that such hazards exist.”

The degree of danger, specifically the “absence, presence, or
magnitude of the biological hazard” was nevertheless indeterminate
because the area was in “flux.” Before conclusions could be drawn,
annual surveys and related laboratory research were necessary to
“determine the mechanisms by which the long and medium half-life
fission products and the important alpha emitters are absorbed and
metabolized by important crops and animals.”

[ebb 866 doc 24]

Document 24

J.H. OLAFSON, H. NISHITA, AND K. H. LARSON, UNIVERSITY OF CALIFORNIA
LOS ANGELES, SCHOOL OF MEDICINE, ATOMIC ENERGY PROJECT, “THE
DISTRIBUTION OF PLUTONIUM IN THE SOILS OF CENTRAL AND NORTHEASTERN NEW
MEXICO AS A RESULT OF THE ATOMIC BOMB TEST OF JULY 16, 1945,”
UCLA-406, 19 SEPTEMBER 1957, UNCLASSIFIED
[[link removed]]

Sep 19, 1957

Source

DOE Open-Net

If any at the AEC had hoped that radiation would dissipate, this UCLA
report, Janet Farrell Brodie later explained, “gave even less
reassurance as the investigators resurveyed areas studied earlier and
corrected earlier findings.” Using new data, the report found that
that “the area originally contaminated by fall-out from the Trinity
detonation was greater than the 1,100 square miles estimated by the
1948 survey,” although a square mile estimate was not provided. The
researchers found plutonium “in amounts up to 0.007 micrograms per
square foot of soil, one-half inch deep, at a distance of 88 miles
northeast of the site of detonation,” with even more, l07 micrograms
per square foot, on the Chupadera Mesa 28 miles northeast of the
detonation site. Thus, there had been “no appreciable decrease in
plutonium content of the soils … due to erosional factors.”

[ebb 866 doc 25]

Document 25

THOMAS E. HAKONSON AND LAMAR J. JOHNSON, LOS ALAMOS SCIENTIFIC
LABORATORY, “DISTRIBUTION OF ENVIRONMENTAL PLUTONIUM IN THE TRINITY
SITE ECOSYSTEM AFTER 27 YEARS,” N.D. [1972]
[[link removed]]

Jan 1, 1972

Source

University of New Mexico, Center for Southwest Research, Szasz Papers,
Box 8, Folder 8

This 1972 report by Los Alamos scientists several decades after the
test found the same overall pattern of plutonium distribution in soil,
vegetation and rodents (“as a function of distance from GZ [Ground
Zero]”) that Olafson, et al. had observed in 1957. Further, they
noted an “increased migration of PU [plutonium] into the soil since
the last measurements were made about 20 years ago.”

[ebb 866 doc 26]

Document 26

CENTER FOR DISEASE CONTROL AND PREVENTION, NATIONAL CENTER FOR
ENVIRONMENTAL HEALTH, DIVISION OF ENVIRONMENTAL HAZARDS AND HEALTH
EFFECTS, RADIATION STUDIES BRANCH, _FINAL REPORT LOS ALAMOS
HISTORICAL RETRIEVAL AND ASSESSMENT (LAHDRA) PROJECT, _NOVEMBER 2010
[[link removed]]

Nov 1, 2010

Source

CDC Website [[link removed]]

Beginning in 1999, the Center for Disease Control began supporting a
detailed study to “identify all available information concerning
past releases of radionuclides and chemicals from the Los Alamos
National Laboratory.” Based on wide access to a number of archives,
the final report, published in 2010, covered a variety of public
exposure issues associated with activities at Los Alamos, from
plutonium reprocessing and beryllium use to hot cell activities and
reactor operations. A major chapter looked closely at the Trinity Test
and its “potential doses to members of the public.” As Brodie
observed, “For the first time, a publicly available government
report provided explanations, tables, and maps of the post-test
radiation.” One particularly shocking finding was that radioactive
exposure rates in public areas” near the test site “measured at
levels 10,000 times higher than currently allowed.”[25]
[[link removed]]

Despite the data provided on post-test radiation, the report did not
draw conclusions about adverse health impacts. According to the
report, “Studies of public exposure had been incomplete because they
had not “reflected the internal doses received by residents [near
the Trinity test] from intakes of airborne radioactivity and
contaminated water and food.” Thus, “too much remains undetermined
about exposures from the Trinity test to put the event in perspective
as a source of public radiation exposure or to defensibly address the
extent to which people were harmed” (10-50). A recent study by NCI
and DOE researchers attempts to fill the gap by estimating numbers of
excess cancers [See endnote 6].

NOTES

[1]
[[link removed]] . 
Robert S. Norris, _Racing for the Bomb: General Leslie R. Groves, The
Manhattan Project’s Indispensable Man_ ( South Royalton, VT:
Steerforth Press,  2002), 395; Alan B. Carr, Alan B. Carr, “Thirty
Minutes Before the Dawn,” _Nuclear Technology_
[[link removed]] 207
Supplement 1 (2021): S2-S3; Sabine Lee, “’Crucial? Helpful?
Practically Nill?’ Reality and Perceptions of Britain’s
Contribution to the Development of Nuclear Weapons During the Second
World War,” _Diplomacy & Statecraft_ 33 (2022), 31. For the
possibility of a test failure, see Alex Wellerstein, "What If the
Trinity Test Had Failed?,"_ Restricted Data: A Nuclear History Blog_,
16 July 2020.

[2]
[[link removed]] . 
Toshihiro Higuchi, _Political Fallout: Nuclear Weapons Testing and
the Making of a Global Environmental Crisis_ (Stanford: Stanford
University Press, 2020), 20.

[3]
[[link removed]] .
 Higuchi, _Political Fallout_, 20.

[4]
[[link removed]] . 
Nelson Eby, Robert Hermes, Norman Charnley, and John A. Smoliga, 
“Trinitite—The Atomic Rock,” _Geology Today_ (2010): 181;
Carr, “Thirty Minutes Before the Dawn,” S11; Norris_, Racing for
the Bomb_, 408.

[5] .  Janet Farrell Brodie, _The First Atomic Bomb: The Trinity
Site in New Mexico_ (Lincoln: University of Nebraska, 2023); Brodie,
“Radiation Secrecy and Censorship After Hiroshima and
Nagasaki.” _Journal of Social History _48 (2015): 842-64, and
Brodie, “Contested Knowledge: The Trinity Test Radiation Studies,”
Brinda Sarathy, Vivien Hamilton, and Janet Farrell Brodie,
eds., _Inevitably Toxic: Historical Perspectives on Contamination,
Exposure, and Expertise_ (Pittsburgh: University of Pittsburgh Press,
2018), 50-73.

[6]
[[link removed]] .
 Apparently what inspired the LAHDRA study were “alarmingly high
numbers of brain cancer” on Los Alamos’ west side. Although it was
later determined that the numbers were a statistical fluke, continued
public concern led the Centers for Disease Control and Prevention to
undertake a study of Los Alamos Laboratory’s impact on Los Alamos
and New Mexico generally. See Ian Hoffman, “Feds To Search for Lab
Toxic Releases,” _Albuquerque Journal_, 24 February 1999.

[7]
[[link removed]] . 
Steven L. Simon, André Bouville & Harold L. Beck, “Estimated
Radiation Doses and Projected Cancer Risks for New Mexico Residents
from Exposure to Radioactive Fallout from the Trinity Nuclear
Test,” _Nuclear Technology_
[[link removed]] Supplement
1 (2021): S380-S396.

[8]
[[link removed]] .
 Brodie, _The First Atomic Bomb_, 166-174; Nora Wendl, “Trinity
Fallout,”_ __Places Journal_
[[link removed]],
June 2024;  Lesley M. M. Blume, “Collateral Damage: American
Civilian Survivors of the 1945 Trinity Test,” _The Bulletin of the
Atomic _Scientists
[[link removed]], 17
July 2023.

[9]
[[link removed]] .  
Brodie, _The First Atomic Bomb_, 171-173.

[10]
[[link removed]] . 
For the 100-ton test, see Carr, “Thirty Minutes Before the Dawn,”
S4-S5; Brodie, _The First Atomic Bomb, _14-19; and Barton C.
Hacker, _The Dragon’s Tail: Radiation Safety in the Manhattan
Project, 1942-1946 _(Berkeley: University of California Press, 1987),
77-83. For “dress rehearsal,” see K[enneth] T.
Bainbridge, _Trinity_, Los Alamos National Laboratory, LA-6300-H, 
May 1976, 7, OpenNet
[[link removed]].

[11]
[[link removed]] .
 Bainbridge, _Trinity_, 9.

[12]
[[link removed]] . 
Brodie, _The First Atomic Bomb_, 17.

[13]
[[link removed]] .
 For Hirschfelder’s explanation of how he and Magee concluded that
the detonation would produce fallout, see “The Scientific and
Technological Miracle at Los Alamos,” in Lawrence Badash et al.,
eds., _Reminisces of Los Alamos, 1943-1945_ (Dordrecht, the
Netherlands: D. Riedel, 1980), 73-75.

[14]
[[link removed]] .
 James L. Nolan, _Atomic Doctors: Conscience and Complicity at the
Dawn of the Nuclear Age_ (Cambridge: Harvard University Press, 2020),
49.

[15]
[[link removed]] . 
Nolan, _Atomic Doctors_, 40, 46.

[16]
[[link removed]] . 
For the origins of the 0.1 r standard, see Hacker, _The Dragon’s
Tail,_ 23-28.

[17]
[[link removed]] .
 Nolan, _Atomic Doctors_, 41-43.

[18]
[[link removed]] . 
See Nolan, _Atomic Doctors_, 43-48, for a review of the issues
involving his grandfather’s memorandum and the legal claims problem.

[19]
[[link removed]] . 
Brodie, _The First Atomic Bomb_, 26-27

[20]
[[link removed]] .
 In _Atomic Doctors_, at pages 51-52, Nolan quotes the Warren
letter, which is in his personal collection and unavailable to
researchers. For further detail on fallout spread after Trinity, see
Higuchi, _Political Fallout, _19-22, and Hacker, _The Dragon’s
Tail_, 102-108.

[21]
[[link removed]] . 
For more on the Ratliffs, see Barton Hacker, _The Dragon’s Tail_,
104-105, and Brodie, _The First Atomic Bomb_, 167-169.

[22]
[[link removed]] . 
Higuchi, _Political Fallout_, 21.

[23]
[[link removed]] .
 Annamaria Haden, “Radioactive Cows
[[link removed]],” _Agricultural
History Society_,  6 November 2023.

[24]
[[link removed]] .
 Brodie, “Contested Knowledge: The Trinity Test Radiation
Studies.”

[25]
[[link removed]] . 
Brodie, _The First Atomic Bomb_, 169

[nuclear.jpg] [[link removed]]

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PHOTO AND VIDEO COLLECTION

To see all related images and videos click here
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[still image from film 4, showing Oppenheimer near Jumbo]
[[link removed]]

Los Alamos laboratory director Robert Oppenheimer monitoring work on
the device for the Trinity test (Still image from Film 4
[[link removed]])

Film 5: The nuclear explosion, 16 July 1945: This excerpt shows the
detonation from different vantage points: the first at ground level
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[Map of the Trinity site]
[[link removed]]

Detailed map of the area to the northeast of Trinity ground zero where
the highest off-site radiation levels were measured after 16 July
1945. The sites identified include the “Hot Canyon” (Hoot Owl
Canyon) and the nearby Ratliff ranch. (Map from _Los Alamos
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[Estimated density of radioactive fallout during the ten days after
the Trinity test]
[[link removed]]

Estimated density of radioactive fallout during the ten days after the
Trinity test.  According to a new study,
[[link removed]] led by
Sébastien Philippe, the fallout reached the entire United States
(except for Oregon and Washington states) along with Canada and Mexico
[ArXiv.org (Cornell University)]

[Identification photo for Dr. Louis Hempelmann]
[[link removed]]

Identification photo for Dr. Louis Hempelmann, the director of medical
and health affairs at Los Alamos, who expressed concern about the
“hazards” of the first atomic test, supported precautionary health
and safety measures, and checked on  several “downwinder”
families during the months after the test. (Photo from _Historic
Badges. Los Alamos National Laboratory_
[[link removed]])

For more images and videos - click here
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