In the 75 years since Hiroshima, nuclear testing killed untold thousands

A mushroom cloud rises over Enewetak Atoll in the Marshall Islands after the first U.S. test of a full-scale thermonuclear device on Nov. 1, 1952. (Los Alamos National Laboratory/AP)

On Aug. 6, 1945, the United States dropped an atomic bomb on Hiroshima that obliterated much of the city and sent a mushroom cloud tens of thousands of feet into the air. After 75 years, it continues to cast a shadow over world affairs.

The bombing of Nagasaki three days later was the second and final time the atomic bomb saw use in war. On Aug. 15, Japan announced its surrender.

The weapons caused unparalleled destruction, snuffing out more than 150,000 lives. But those were not the last people to die as a result of nuclear detonations.

In the decades since 1945, the United States, the Soviet Union and at least six other countries set off a total of more than 2,000 nuclear test explosions, which caused tens of thousands of deaths around the world, according to some estimates, along with displacement and environmental degradation that long remained secret and continue to affect communities today.

75 years of nuclear detonations

10,000 kilotons United States U.S.S.R. United Kingdom
2,000 China France India, Pakistan, North Korea, Unknown
10,000 kilotons    
2,000 United States
U.S.S.R. United Kingdom
China France
India, Pakistan, North Korea, Unknown
Showing tests performed through 1945 Start animation

During World War II, the Soviets began spying on U.S. nuclear efforts and, after the war, a nuclear arms race took shape.

The competition to develop stronger nuclear devices took a human toll. Both governments subjected people at home and abroad to high radiation levels, sometimes with indifference. “Scientists in the 1950s were certainly aware of risks” posed by tests, said Jacob Hamblin, an Oregon State University researcher. “Military demands — not necessarily in wartime — provided a justification for exposing large numbers of people, often under a veil of secrecy.”

No country has conducted more nuclear tests than the United States, which set off its first atomic bomb, in a test code-named Trinity, in New Mexico several weeks before Hiroshima. The barrage of tests that followed wrought a trail of destruction that stretched across continents and decades.

An aerial view after the first atomic explosion, at Trinity test site in New Mexico on July 16, 1945. (AP)

No one has calculated an accurate global body count linked to nuclear testing, or a figure for major U.S. test sites. The United States conducted tests in Nevada, which saw nearly 1,000 nuclear tests, and the Marshall Islands (located between Hawaii and the Philippines), which saw 67. The effects of the testing have often manifested as an increase in cancer rates. Estimates of the number of people who have died as a result of atmospheric tests conducted by the United States from the 1940s through the 1960s range from more than 10,000 to an order of magnitude beyond that.

When tests began in the Marshall Islands in July 1946, U.S. officials relocated inhabitants, promising them they could soon return.

For many of them, that was never possible.

Some islanders were exposed to high levels of radiation. In the March 1954 Castle Bravo experiment, when U.S. engineers vastly underestimated the impact of a thermonuclear explosion 1,000 times stronger than the Hiroshima bombing, radioactive material rained down on nearby coral reefs, islands and their inhabitants.

The Marshall Islands were exposed to the daily equivalent of 1.6 Hiroshima-sized explosions between 1946 and 1958, if the impact were spread evenly. Last year, a Columbia University study found that radiation levels in some areas there are still “far higher than in areas affected by the Chernobyl and Fukushima nuclear disasters.”

Observers on the bridge of the USS Mt. McKinley observe a mushroom cloud over Bikini Atoll in the Marshall Islands on July 1, 1946, during the U.S. military's “Operation Crossroads” tests. (Jack Rice/AP) (Jack Rice/AP)

Residents of Bikini Atoll wave goodbye to their home from a Navy ship transporting them to a new place to live, Rongerik Atoll, more than 100 miles away, on March 16, 1946. Bikini Atoll remains contaminated by radiation. (Clarence Hamm/AP) (Clarence Hamm/AP)

Observers on the bridge of the USS Mt. McKinley observe a mushroom cloud over Bikini Atoll in the Marshall Islands on July 1, 1946, during the U.S. military's “Operation Crossroads” tests. (Jack Rice/AP) Residents of Bikini Atoll wave goodbye to their home from a Navy ship transporting them to a new place to live, Rongerik Atoll, more than 100 miles away, on March 16, 1946. Bikini Atoll remains contaminated by radiation. (Clarence Hamm/AP)

Hilda Heine, who was president of the Marshall Islands until January, told The Washington Post, “a lot of the critical information was not disclosed” at the time of the tests. In the following decades, she said her people faced “broken promises” and insufficient compensation from the United States.

The United States has refused to pay $2.3 billion in damages awarded to the Marshall Islanders by a nuclear claims tribunal. And victims in the continental United States have faced similar legal hurdles: The U.S. Radiation Exposure Compensation Act does not cover those all affected and is set to expire in two years unless it is extended.

Soldiers assigned to witness atmospheric tests in Nevada through 1962 were also among those exposed to radiation. A report by the Centers for Disease Control and Prevention and the National Cancer Institute found that testing may have led to thousands of deaths: The report said at least 11,000 U.S. cancer deaths may be attributable to the atmospheric tests between 1951 and 1962.

According to research by Keith Andrew Meyers, an economic historian, the atmospheric tests may have affected a wider area than originally assumed, casting radioactive particles across a swath of the United States and affecting mortality patterns on a grand scale, leading to at least 145,000 deaths between 1952 and 1988.

Nuclear testing “has always been disproportionately felt by already marginalized communities,” said Matt Korda, a researcher with the Federation of American Scientists’ Nuclear Information Project. “The U.S. government and the scientific community essentially lied to residents who were living around those sites in Nevada as well as Marshall Islanders about the dangers of radiation exposure.”

The first Soviet test of a thermonuclear weapon, at the Semipalatinsk test site, on Aug. 12, 1953. (Hulton Archive/Heritage Images/Getty Images)

Victims of the nuclear age

The Soviet Union chose Semipalatinsk in Kazakhstan as its primary testing site.

Health authorities in Kazakhstan believe that atmospheric tests exposed up to 1.5 million residents to radiation. The impact may not yet be understood in full. Research cited by the journal Nature suggests adverse cardiovascular affects may be passed down to future generations.

Other countries caused similar problems. Activists in Algeria and French Polynesia continue to blame Paris for radioactive waste left behind after tests, along with lingering health consequences. Britain conducted its initial nuclear tests in Australia, where a Royal Commission later found that they put residents at risk and were prepared with negligence. Britain later moved its tests to Malden Island and Kiritimati (a.k.a. Christmas Island) in the Pacific, where U.K. and U.S. explosions caused ecological damage and threatened the health of locals.

The French military base on Mururoa Atoll, 750 miles southeast of Tahiti, in French Polynesia, in 1995. The French government offered for the first time in 2009 to compensate people who suffered health problems as a result of nuclear tests in Algeria and the South Pacific decades ago. (Francois Mori/AP)

In 1963, the Partial Nuclear Test Ban Treaty — signed by the Soviet Union, the United Kingdom, the United States and later more than 100 other countries — prohibited all but underground detonations, but France and China conducted atmospheric tests for more than another decade. China conducted a number of tests in Xinjiang, home of the country’s suppressed Uighur Muslim minority.

In the United States, underground tests came to an end in the early 1990s, after the fall of the Berlin Wall marked the end of the Cold War, and other nations soon followed suit.

In 1996, President Bill Clinton signed the Comprehensive Nuclear-Test-Ban Treaty, which has since been signed by 183 other countries. Even though the U.S. Senate later refused to ratify the treaty, no known nuclear weapons tests have since been conducted by the United States.

Chart key

Number of nuclear tests that year

Estimated nuclear stockpile

United States

1,032 total tests

The United States

heavily reduced its nuclear

stockpile in the early 1990s.

96 nuclear tests in 1962.

31,255

warheads

1945

1992

The U.S.S.R.’s stockpile peaked in 1986 at 40,159 warheads.

U.S.S.R.

715

1949

1990

U.S., U.S.S.R. and U.K. temporarily agree to stop all nuclear testing.

United Kingdom

45

1952

1991

France

210

1960

1996

China

45

1964

1996

India

3

1998

1974

Pakistan

2

1998

North Korea

6

2006

2017

North Korea’s recent tests have been

heavily condemned.

Chart key

Number of nuclear tests that year

Estimated nuclear stockpile

United States

1,032 total tests

The United States

heavily reduced its nuclear

stockpile in the early 1990s.

96 nuclear tests in 1962.

31,255

warheads

1945

1992

The U.S.S.R.’s stockpile peaked in 1986 at 40,159 warheads.

U.S.S.R.

715

1949

1990

U.S., U.S.S.R. and U.K. temporarily agree to stop all nuclear testing.

United Kingdom

45

1952

1991

France

210

1960

1996

China

45

1964

1996

India

3

1998

1974

Pakistan

2

1998

North Korea

6

2006

2017

North Korea’s recent tests have been

heavily condemned.

Chart key

Number of nuclear tests that year

Estimated nuclear stockpile

United States

The United States performed

96 nuclear tests in 1962.

The United States heavily reduced its nuclear stockpile in the early 1990s.

1,032 total tests

31,255 warheads

1945

1992

U.S.S.R.

The U.S.S.R.’s stockpile peaked

in 1986 at 40,159 warheads.

715

1949

1990

U.S., U.S.S.R. and U.K. temporarily agree

to stop all nuclear testing.

United Kingdom

45

1952

1991

France

210

1960

1996

China

45

1964

1996

India

3

1998

1974

Pakistan

2

1998

North Korea’s recent tests have been

heavily condemned.

North Korea

6

2006

2017

Chart key

Number of nuclear tests that year

Estimated nuclear stockpile

The United States performed 96 nuclear tests in 1962.

“Castle Bravo,” the

most powerful test in

U.S. history, takes place.

The United States heavily reduced its nuclear stockpile in the early 1990s.

31,255 warheads

United States

1,032 total tests

1945

1992

The U.S.S.R.’s stockpile peaked

in 1986 at 40,159 warheads.

U.S.S.R.

715

1949

1990

U.S., U.S.S.R. and U.K. temporarily agreed

to stop all nuclear testing.

United Kingdom

45

1952

1991

France

210

1960

1996

China

45

1964

1996

India

3

1974

1998

Pakistan

2

1998

North Korea’s recent tests have been

heavily condemned.

North Korea

6

2006

2017

Chart key

Number of nuclear tests that year

Estimated nuclear stockpile

The United States performed

96 nuclear tests in 1962.

“Castle Bravo,” the

most powerful test in

U.S. history, takes place.

The United States heavily reduced its nuclear stockpile in the early 1990s.

31,255 warheads

United States

1,032 total tests

1945

1992

The U.S.S.R.’s stockpile peaked

in 1986 at 40,159 warheads.

U.S.S.R.

715

1949

1990

U.S., U.S.S.R. and U.K. temporarily agreed

to stop all nuclear testing.

United Kingdom

45

1952

1991

France

210

1960

1996

China

45

1964

1996

India

3

1974

1998

Pakistan

2

1998

North Korea’s recent tests have been

heavily condemned.

North Korea

6

2006

2017

China, India and Pakistan also halted their nuclear tests in the late 1990s. Only North Korea has conducted tests this century, all six of them between 2006 and 2017.

A toxic legacy lingers, and new risks emerge

Crew members of Dai 5 Fukuryu Maru attend a news conference at the Tokyo University Hospital on March 16, 1954. All 23 crew members of the boat were exposed to nuclear fallout from the U.S. Castle Bravo nuclear test while fishing for tuna near Bikini Atoll on March 1, 1954. Chief radio operator Aikichi Kuboyama died six months later. (The Asahi Shimbun/Getty Images)

Over the three-quarters of a century since Hiroshima, Japanese activists have taken a firm stand against nuclear testing. The 1954 Castle Bravo test in the Marshall Islands, which contaminated a nearby Japanese fishing boat, led to the creation of the Japan Council Against Atomic and Hydrogen Bombs (Japan Gensuikyo). The organization dispatched experts to communities affected by tests around the world to help build relief campaigns.

The victims with whom Japan Gensuikyo has been in touch range from “Fiji islanders who were mobilized to work in the British nuclear testing in the Pacific,” to American soldiers “who took part in nuclear tests in the Pacific or Nevada” and “indigenous people irradiated at uranium mining,” Hiroshi Taka, a director of the organization, said in an email.

Meanwhile, fears of a resurgent nuclear arms era are on the rise.

North Korea has conducted a handful of nuclear tests. The most recent one, in 2017, was powerful enough to reshape the mountain above it.

In May, the Trump administration discussed whether to break the United States’ decades-long moratorium and conduct the first U.S. nuclear test explosion since 1992 — and the first known test this century by a nation other than North Korea, The Washington Post reported. The goal, according to a senior administration official who spoke to The Post, would be to put pressure on China to agree to a follow-on agreement to the Obama-era New Strategic Arms Reduction Treaty (New START) with Russia.

The United States “continues to observe the 1992 nuclear test moratorium,” said Greg Wolf, a spokesman for the U.S. National Nuclear Security Administration. “NNSA maintains the readiness to conduct an underground nuclear test within 24 to 36 months, if required to ensure the safety and effectiveness of the nation’s stockpile.”

Nonproliferation experts warn that a return to testing would inflame international tensions.

“Conducting a test and breaking a moratorium that they’ve had for so many years just sends a signal to other countries that it’s okay to do the same,” said Korda, the nonproliferation researcher. As the world commemorates Hiroshima and Nagasaki, he said, the announcement of a U.S. test would be “a giant middle finger to the survivors.”

Sources: Johnston’s Archive, State Department, Bulletin of the Atomic Scientists. Graphics by Kevin Schaul and Armand Emamdjomeh.

Rick Noack

Rick Noack currently covers international news from The Washington Post's Berlin bureau. Previously, he worked for The Post from Washington as an Arthur F. Burns Fellow and from Britain, Australia and New Zealand.

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