Biological Warfare in the Korean War: Allegations and Cover-up

By Thomas Powell


I weigh into the subject of biological warfare (BW) with trepidation. It’s not my field of study. It was in fact, my father’s topic which he researched quite thoroughly, both in China in 1951-53, and later in the US in 1977-83. John W. (Bill) Powell was editor and publisher in Shanghai of the English-language news magazine, China Weekly Review (after 1952, China Monthly Review [CMR]). The Review first published reports from North Korean military sources of alleged US germ warfare attacks on North Korea in March 1952.1 The Review continued to print the growing number of reports of US Army BW attacks in North Korea and China and covered the international uproar until 1953. Powell considered these reports reliable as they came directly from North Korean and Chinese government officials citing eye-witness testimony, laboratory tests, and People’s Volunteer Army (PVA) field reports.2 The US government vehemently denied the allegations and tar-brushed the Review as a mouthpiece of the Chinese communist government. With falling subscription revenues in post-Revolution Shanghai, the Review folded in 1953,3 and my family returned to the US, settling in San Francisco. In 1956, Bill Powell, my mother, Sylvia Powell, and their associate editor, Julian Schuman were indicted on federal charges of sedition for the editorials and news content of the Review. Sedition is a complex charge designed to put limits on freedom of speech and the press in times of war. It is a serious criminal offense carrying fines of $10,000 and prison sentences up to 20 years on each count. The defense options were limited, but ultimately, my parents chose to fight based on the truth of their claim; the US government had used BW in North Korea and China during the Korean War and they would substantiate it. The case came to trial in 1958 and ended abruptly with a mistrial being declared by the judge.4 Charges lingered until 1961 when new Attorney General Robert Kennedy dropped the indictment.

The government’s case against my parents collapsed because the prosecution would not allow defense access to top-secret Defense Dept. and State Dept. records which might have validated Chinese and North Korean BW accusations, nor was it willing to permit BW physical evidence collected in China to be introduced into a US court, nor would it permit in-person courtroom testimony by North Korean and Chinese eye witnesses to alleged BW attacks.5 Powerful Senators and top State Dept. officials wished to punish my parents for the editorial policy of their newspaper which supported the new communist government in China, and which had published the North Korean and Chinese allegations of BW use by the US Army in combat. However, these powerful parties were also not willing to allow the defense to mount a case based upon the evidence of the BW claims. The prosecution wanted to punish dissent while maintaining state secrecy, which Judge Goodman, fortunately, would not permit.

In 1976, a Japanese television station ran an investigative documentary about Japan’s BW program located near Harbin, Manchuria from 1937-1945.6 This BW prison camp was designated as a water purification plant, and had the innocuous name of Unit 731. It was commanded by Surgeon General Shiro Ishii. Unit 731 undertook lethal human experimentation by inoculating prisoners with bubonic plague, hemorrhagic fever, and many other diseases to scientifically record the progress of infection and death. Japanese camp surgeons performed live vivisections on infected victims to autopsy diseased organs. They conducted frostbite experiments, forced pregnancy on women prisoners, dissected infected fetuses, removed brain tissue and limbs of live prisoners, dosed Caucasian and Asiatic prisoners with fatal pathogens to determine possible racial differences in natural immunity, and numerous other gruesome acts of torture. Conservative estimates claim 3,000 prisoners were murdered at Unit 731.7 Another estimated 400,000 civilians were killed by infectious disease such as cholera and anthrax when ceramic bombshells containing these pathogens were dropped on Chinese cities and villages. The Japanese film crew discovered former Unit 731 personnel pursuing professional careers or living quietly in retirement even though they had been responsible for some of the worst war crimes carried out by Japan during World War II. The story didn’t get much traction outside of Japan.

With the impetus of the Japanese documentary and the recently enacted Freedom of Information Act (FOIA), Bill Powell again took up the Korean War BW allegations. A portion of his research was summarized in his article, “Japan’s Biological Weapons, 1930-1945,” in the October 1981 Bulletin of Atomic Scientists.8 The topic for its day “went viral” and Powell appeared on segments of 60 Minutes, 20/20, People Magazine and similar news outlets in Japan and South Korea. Media coverage also ignited renewed academic interest in the topic, and several books and articles on the history and atrocities of biological warfare have subsequently been published.

Through FOIA, Powell was able to trace the history of Unit 731, including its extensive medical and autopsy reports.9 Dr. Ishii’s career as camp commandant was illuminated, and Powell discovered that following Japan’s unconditional surrender in August 1945, Ishii and much of his top staff had escaped from Harbin down the Korean Peninsula where they commandeered passage to Japan.10 If he had been captured by any of the armies in the neighborhood, Peoples Liberation Army, Kuomintang, Soviets or Korean communist, he would have been tortured, deprogrammed, tried and likely hanged. But Ishii had prepared his escape back to Tokyo with his core scientific team and a cache of research documents including 8,000 microscope slides which he then parlayed to the American victors in exchange for immunity from war crimes prosecution.

The US Army quickly dispatched Camp Detrick microbiologist, Lt. Col. Murray Sanders to investigate Army Intelligence reports of the Harbin BW factory and to interview the Japanese scientists. Although Sanders proved ineffectual as an interrogator, he recognized the military value of disease pathology on live human subjects and, despite its criminality and repugnance, recommended that a deal be cut. Gen. MacArthur promptly signed off on the deal.11 Ishii and his research team were secretly granted immunity from war crimes prosecution in exchange for their research. The Japanese BW scientists were extensively deprogrammed by American intelligence personnel while the BW research was discreetly shipped to the Army’s biological research facility at Fort Detrick, Maryland where it quietly entered the US weapons arsenal.12

If the US had prosecuted Ishii, Unit 731 BW research would have had to be shared with the USSR.13 Shielding Ishii accelerated the Cold War, and led to the massive Soviet BW weapons build-up of the 1970s-80s.14 No mention of Ishii or Unit 731 was raised by US prosecutors at the 1946 Tokyo War Crimes Tribunal. However, the Khabarovsk War Crimes Trials held by the Soviet Union in 1949 prosecuted General Otozo Yamada, Commander-in-Chief of the Japanese occupying army, and his top officers for biological warfare crimes. Many of the victims of Unit 731 had been Russians.15 Soviet prosecutors accused the US of harboring Ishii to keep the BW research secret. While the trial was widely publicized abroad, the US dismissed Soviet allegations as communist propaganda.

The US government to this day denies ever having experimented or used biological weapons in North Korea and China during the Korean War. There have been various claims and counterclaims among historians. After many long years of digging in Pentagon records through FOIA, Powell was never able to find any document, not even a heavily redacted one, which proved or even admitted that the US Army used biological warfare in Korea. He never quit believing the US had engaged in germ warfare, but he understood he was not going to find the incontrovertible paper trail. The record was scrubbed. The more he dug, the deeper things got buried.16


The Korean War was one more horrific slaughter in the great global bloodletting which was the 20th Century. While the war lasted only three years (June 1950-July 1953), the entire built infrastructure of both North and South Korea was completely destroyed. Estimates of all casualties vary widely, from a low of 1.2 million to a high of 4.5 million.17   Civilians suffered the most. In one purge called the Bodo League Massacre ordered by South Korean President Syngman Rhee, more than 100,000 suspected leftists, intellectuals and civil servants with their families were summarily executed. More than 33,000 American soldiers also died in Korea. Casualties of North and South Korean soldiers and Chinese soldiers were in the hundreds of thousands.

The Korean War has been called “America’s forgotten war.” But recently, the subject of US Army BW use in the Korean War has resurfaced with a reworked version of a dramatic claim by Milton Leitenberg.18 In a recent essay Leitenberg revisits his earlier claim that the Chinese and North Korean BW accusations against the US during the Korean War was all a giant hoax perpetrated by Stalin, Mao Zedong, and Zhou Enlai. According to Leitenberg the BW accusations were a Cold War ploy to orchestrate international public opinion against the US-led war in Korea. Citing two primary sources, the 1998 public disclosures of the Soviet Central Committee19 and a memoir by Wu Zhili, Director of the People’s Volunteer Army Health Division during the Korean War, Leitenberg lays out a narrative of deceit and fabricated BW evidence from the highest levels of Soviet and Chinese government.

According to Leitenberg, the communist accusations in 1952 of a widespread American BW campaign were “a grand piece of political theater.” The physical evidence shown to the International Scientific Commission (ISC) in 1952 as proof of US Army BW attacks was fabricated; Dr. Joseph Needham and his investigative team were duped. The US Army did not engage in a biological warfare campaign just as it has continuously denied. Leitenberg exonerates the US Army of any biological warfare deployment in the Korean War.

Leitenberg’s claim of a massive communist hoax is an interesting spin, but the conclusion he draws that the US never used BW during the Korean War is not warranted from his research and is simply not believable.20 Leitenberg’s thesis amounts to a conspiracy theory. It presumes that the Chinese and North Koreans possessed advanced scientific knowledge and technical skill with bio-hazardous materials in 1952 in order to falsely produce the physical evidence presented to the ISC, or perhaps, the assumption is that the physical evidence was acquired from the Soviets? Secondly, it presumes the communists had the capacity for the mass production of plague infected fleas and other vectors that were reported by eye witnesses and collected as evidence in the theater of war. Thirdly, it presumes that Dr. Needham and his scientific colleagues on the ISC were gullible and easily duped. Leitenberg categorically and cavalierly dismisses the ISC’s “massive 669 pages” of findings without specific and itemized refutation of any one named document, report or support material including the testimony of witnesses, the actual evidence examined, the study’s methodology, transcripts of lengthy discussions among the commission members, or the study’s conclusions. Lastly, a hoax of this scale would require a theatrical production team with a cast of thousands to cause local outbreaks of plague and hemorrhagic fever in China and North Korea, and to locate victims willing to become diseased human corpses. The necessary resources and the collaboration required between disease victims, soldiers, scientists, top party officials and international observers to create a BW hoax on the global stage in the midst of the raging and bloody Korean War, and all the above accomplished in secret, and kept secret for five decades— this conspiracy thesis is simply not credible.

Furthermore, in spite of this conceptual improbability, if Stalin, Mao Zedong, and Zhou Enlai pulled off this BW hoax of monumental proportions to tar-brush the US as Leitenberg claims, the hoax was therefore a great success. By accusing the US of biological warfare, the Communists succeeded in handcuffing General MacArthur from using this advantageous new weapon. The ruse soured international support for the UN war effort and denied the US Army a new tactical advantage. By clever subterfuge and to the chagrin of Harry Truman and Dean Acheson, the entire hawk cartel in Washington was politically out-maneuvered by this Cold War, high-stakes communist gambit. Leitenberg’s hoax thesis is a B-movie plot made marginally plausible with our removal in time from the historical events of the Korean War. It does not spin well with US self-image, and it is hardly likely that any of the American principals of this historic episode, especially the generals who are now long dead would agree with his characterization.


Leitenberg’s is only the latest voice in a sixty-five year litany of Korean War BW cover-up by US government officials and its surrogates. Few Americans today have any knowledge of the Korean War, and fewer yet have ever heard rumor of America’s big, ugly germ warfare secret. This history has been erased, and national memory successfully cleansed. America’s self-righteous image at home has been maintained. The BW cover-up, in spite of occasional breaches, has long been a success story in America’s clandestine history.

The cover-up began immediately following the first North Korean allegations in 1951. The Truman administration categorically denied the allegations, and set in motion what has long been an unwritten chapter in American history. When new BW allegations were launched by China and North Korea in 1952, the “plausible denial” spin had already been worked out by Acheson to deal with the international and domestic press. When Eisenhower assumed the presidency in 1953, he brought in the rabidly anti-communist John Foster Dulles21 as Secretary of State and promoted his brother Allen Dulles to CIA Director. The plausible denial machinery became locked in place.

One common omission among Korean War BW deniers is they do not differentiate between the first accusation of American BW use by North Korean Foreign Minister Pak Heong-yeong (Bak Hong-yong) on May 8, 1951 and subsequent accusations on February 22, 1952. Pak’s first allegation designated a specific four-week window of germ attacks from December 1950 to January 1951. This is a pivotal point in the war when the UN Force is in full retreat from the Chinese PVA counter-invasion across the Yalu River. In this battlefield scenario, disease-infected chicken feathers were spread as a defensive tactic to cover the retreating UN Forces and slow down the Chinese PVA advance.22 The winter 1950-51 BW deployment is militarily relevant, as spreading infectious disease now enters the repertoire of scorched earth tactics of retreating armies which historically include plundering goods, abducting women and girls, slaughtering civilians and livestock, burning towns, setting forest fires, poisoning wells, and sowing salt.

This first accusation of BW did not get the airplay or produce the international uproar which accompanied the 1952 BW allegations, by which time the war had stalemated near the 38th Parallel. The 1952 testimony accuses US planes of dropping bombs of diseased insects and rodents as an offensive tactic to spread panic and cause massive disease outbreaks in military and civilian populations in North Korea and China. Outbreaks of hemorrhagic fever and plague were reported. Both military and civilian populations were infected. For historical accuracy, tactical differences, and the time-lapse between deployments, there should be differentiation between the defensive “in retreat” BW attack of 1950-51 and the 1952 offensive attacks which aimed to break the stalemate. Clearly there was a strategic pause to design the second accelerated deployment marked by the change of command from MacArthur to Ridgeway.

The promise and the terror of germ warfare is that it sows both fear and death. BW carries the potential to severely debilitate an adversary’s war effort by spreading fatal disease in pandemic proportions. It is terrifying to the attacked population and therefore psychologically insidious. Most people will cringe at the thought of infectious disease used as a weapon of war against civilians. Humans have poisoned their neighbors’ wells for a long time, but weaponizing disease to create mass death carries warfare carnage to a different level of criminality and moral repugnance. It is an ugly stigma for a state to wear.

In spite of its horror (and perhaps because of it as well) bio-warfare is strategically useful as a weapon in some conflict scenarios, but not all. A successful BW attack in a military conflict initially requires secrecy and stealth to render a debilitating blow upon the unprepared adversary. A colonial power could use this weapon successfully against a rebellion or separatist force that had little capacity to cope with the disease outbreak. That military advantage is neutralized in conflicts with adversaries who possess their own germ weapons and can retaliate in kind. Today, there are many states with advanced military BW capacity.23

Currently there is widespread concern that BW could be used by rogue states and bio-terrorists. However, back in 1950, the Chinese and Soviets had already experienced Japanese BW attacks since 1937 from Unit 731. They quickly recognized the evidence after the first US Army attack in December 1950. They well knew how lethal BW could be. They also clearly understood how vulnerable they were. The US had acquired Ishii’s Unit 731 research and lied about it to the world as revealed in the 1949 Khabarovsk Trials. The American BW threat was very real; it would be devastating and it required immediate civil defense countermeasures.24


Another piece of critical historical evidence which is avoided by BW deniers is the swashbuckling but murky role of General Crawford Sams. Sams personally conducted one strange mission behind enemy lines with the stated intent to kidnap a North Korean People’s Army (KPA) plague victim from a hospital bed.26 Sams commanded the Naval vessel, US Infantry Landing Craft No 1091, which Newsweek dubbed the “Bubonic Plague Ship” that was on a “secret mission” at Wonsan Harbor in North Korea. That secret mission remains classified today; however, it has been alleged that this ship, “although masquerading as an epidemic control ship, was actually loaded with bacteriological installations and was used for testing germ weapons on North Korean and Chinese prisoners.”26 Will the Pentagon ever come clean on the true nature and role of this ship? Access to the ship’s original design, blueprints, and dry dock logs would reveal laboratory refitting to determine its bio-weapon manufacturing potential. A review of the ship’s ladings records, crew manifest and visitor log from 1950-53 would identify vector deliveries from the US or Japan, and it would ascertain if any former Japanese BW scientists from Unit 731 were employed.27

The confessions of American pilots shot down over North Korea and China are not fabricated stories. The technical details revealed in the confessions describing the mechanisms of BW bombs, the bomb-loading protocol, and the pre-flight briefings are not made up material, but are factual, eye-witness accounts of the state-of-the-art delivery systems of germ warfare in 1952. The details of their payload, pre-flight briefings, and the pilots’ individual knowledge including sortie dates and names of briefing officers precludes the possibility of invented information.28

However, the American POW pilots unanimously recanted their BW confessions after they were repatriated home. The official US explanation for the confessions was “brainwashing” and physical torture.29 The pilots who confessed to dropping germs had been brainwashed by the Chinese Communists through an insidious new psychological torture method which “inserted false memories into their minds.” This explanation allowed for the lenient treatment of returning POW pilots who might otherwise have faced severe disciplinary action for their confessions. Meanwhile, the pilots were deprogrammed and placed under great pressure to conform. As they remained soldiers there was the veiled threat of court-martial vs. the benefits of honorable discharge and the GI Bill. The aggressive prosecution of other dissidents as public examples, the wholesale destruction of records, and the general tying off of loose ends became standard operational modality of the denial machine.

The logic of plausible denial is not new to official state practice, but it is analyzed at this time and given a name. It follows a standard procedure in criminal trials for the defense to propose alternative scenarios to cast doubt upon the prosecution’s case. If an event such as an outbreak of bubonic plague in a Korean village has an alleged cause such as the deliberate spreading of infected fleas by a US airplane witnessed by local farmers, but an alternative possible scenario is proposed by American officials such as poor local public healthcare in the midst of warfare which is also likely to be true, the two explanations therefore negate each other regardless of whether one or both is true. This is deniability.30

However plausible, to deny is not the same act as to refute or to disprove. The US Army denied the role of the plague ship, but it produced no evidence to disprove the charge. Instead, the US Government moved to drop charges against the Powells rather than permit trial defense experts to examine this vessel. Denying an allegation does not require substantiating evidence or proof and is a much lower standard for truth. The US position on the Korean War BW allegations has consistently taken the form of denial. President Truman denied that the US was using biological weapons in Korea. Subsequent lower level deniers such as Leitenberg brandish Truman’s statement as evidence of US innocence. This compounding of denial amounts to layered obfuscation and is academically questionable.

The internal workings of the plausible denial machine became evident when the ISC report concluded that the testimony and evidence of American germ warfare attacks against North Korea and China in 1952 was irrefutable. The US Army had indeed engaged in systematic BW attacks.31 The first official American response was to tar-brush the Commission scientists as dupes and communist sympathizers. To discredit the report, various credentialed authorities (such as the Director of the NYC Museum of Natural History) volunteered their “objective scientific” opinions. The denial spin job was an extended exercise in innuendo, scorn, belittlement, dismissal, false logic, patriotic rhetoric, red phobia and character assassination. Factual refutation of the report’s findings was slim.

The mindset of plausible denial further presumed that Mao and Kim Il Sung did not already anticipate the American use of BW before the start of the Korean War. Given the Ishii amnesty deal and the Khabarovsk trial findings, the Communist leadership had already calculated the risk of American BW attack into their war strategy, and they were prepared to accept high casualties to finally expel all foreign colonizers from East Asia. The US underestimated both the resolve and the preparedness of the Chinese and North Korean Communists.

One final argument put forward by Leitenberg and other BW deniers is that the US had no offensive BW program until 1953. This statement is an outright falsehood. The US Army in 1942 initiated the Biological Warfare Division within the Army Chemical Corps at Camp Detrick, Maryland. The Unit 731 research was acquired in 1947. There was plenty of time to make BW weapons operational before the onset of the Korean War.32

Attached to this above concern is whether Harry Truman would have signed off on using biological weapons against global communism. Clearly, BW could not be used in the war without his prior approval. Truman had already dropped two atomic bombs on Japan killing a quarter million people. The rationale for the atomic bomb use in 1945 was to shorten the war, avoid the need to invade Japan, and therefore save American soldiers’ lives. As early as November 1950, President Truman had announced that he was considering using the atomic bomb against North Korea or China. However, North Korea provided few strategic targets for an atomic bomb detonation, while major Chinese cities were far removed from the battlefield. There was no strategic or politically viable atomic bomb target. If BW could save American soldiers and shorten the Korean War, Truman approved it. He wasn’t a subtle thinker.


Endless denial breeds skepticism. The more denial is heaped upon a subject, the less plausible that denial becomes. In small doses plausible denial is a sales pitch which reinforces the ideological beliefs a society holds about itself. The post-war Truman Administration elite in Washington and the US Army command in occupied Japan held strong colonial and racial attitudes towards Asians. Chinese and Korean peasants were thought to be “backward,” and would not comprehend the deliberate and immediate cause of a disease outbreak. However, the reality is that peasants tend to be necessarily practical. If a Korean farmer saw a plane fly over, canisters fall out and insects emerge from those fractured containers, that practical farmer would likely attempt to round up and set fire to the pestilence immediately, not save it in a neatly labeled specimen jar. If the farmer lived within a 500-mile radius of Harbin, he would have heard of the eight years (1937-45) of Japanese germ attacks in China, Manchuria, and Siberia. The hubris of the American BW attack was to presume the Chinese and Korean peasants were simple, that they would not immediately discover the germ attack, take suppressive action, and report the incidents promptly to civil and military authorities.

The Korean War is notable in military history for its three separate and successful invasions and their subsequent reversals all within a year. First, the surprise attack of the KPA across the 38th Parallel drove the Republic of South Korea army (ROK) to the Pusan perimeter at the southernmost tip of the Korean Peninsula; second, the US Army-led UN Force counter-invasion at Inchon severed the KPA and cut off their supplies. The UN Force then pursued the remnant KPA northward across the Yalu River. This incursion into China triggered the Chinese People’s Volunteer Army (PVA) to counter-invade across the Yalu River driving US/UN Forces southward back to the 38th Parallel. Battle lines seesawed, but eventually stalemated near where the war had begun. A lot of denial scholarship removes the BW issue completely out of the context of war. The American attacks occurred within the shifting fortunes of intense ground war with heavy casualties on both sides, and the pending threat of nuclear confrontation with Russia.

The collected testimony and evidence is overwhelming that the US did use biological warfare during the Korean War, both in retreat in 1950-51, and offensively to gain ground and bargaining chips in the 1952 stalemate. The CIA and the Pentagon have succeeded in burying the bomber manifests, the plague ship records, and similar routine documentation that would incontrovertibly affirm US culpability. This record-keeping evidence was thoroughly culled and shredded long ago. Higher tier evidence such as correspondence and reports will remain top secret and inaccessible. Hence official denial and academic fence-sitting will continue to abound.

Meanwhile, the contentious issue of “whether or not” the US engaged in massive BW war crimes in the Korean War has evolved. Academic interest has shifted onto the workings of the government denial machine,33 and the imposition of the American security state at its post-WWII inception. The Korean War BW cover-up was an early success story encompassing all the international intrigue and domestic strong-arm tactics that were developed as the “go to” methods to impose state secrecy by government officials. Plausible denial has since become the automatic and entrenched method of maintaining government secrecy.

The question arises why continue this imposed secrecy? After all, most of the soldiers, scientists, and politicians who had important roles in the Korean War BW attacks and the subsequent cover-up are long dead. So why not look at this suppressed chapter of American history and Korean history and Chinese history, and learn something? It appears there are many reasons for maintaining denial. First, the denial machine has worked well so far. BW accusations have been marginalized. Top secret documents remain indefinitely inaccessible so there is no inclination on the part of the Army or the CIA to confess. The subject rarely arises anyway. The bet going forward by top military brass is that the routine of denial will continue to be the best hand.

A second reason for continued denial is that the Korean War fighting ended in a ceasefire which has been in effect since July 27, 1953. There has never been a negotiated truce, and hostilities between the US and North Korea have not ended. The Korean Peninsula remains divided and heavily militarized at the 38th Parallel. The US Army, in addition to the BW attacks, dropped 33,000 tons of napalm, and over 400,000 tons of explosive ordnance. North Korea was carpet-bombed with millions of people killed. The built infrastructure which had been modernized under a half century of Japanese colonial occupation was completely destroyed. No war reparations have ever been paid to North Korea, no Marshall Plan, no Development Bank, and no normalization of relationship. A formal truce settlement would require the US to fess up to its military excesses.

Who won the Korean War (?) is another reason the US Army wishes to keep the BW assault hushed up. Even with the new, secret, highly touted disease weapon, and the textbook setting of rural isolated towns in which to deploy it, the Army’s well-orchestrated BW attack in 1952 was not effective in moving the battle line. For the first time in its very active military history going back to the War of Independence, the US Army was fought to a draw in Korea. The next Asian war against communism a decade later in Viet Nam ended decisively in a loss, another first for the US Army. The sobering score card of America’s colonial military setbacks in Asia in the second half of the 20th century forced the Army to critique its combat tactics, most notably its reliance on conscript soldiers.

But BW is a very dirty deed in the moral register of most human beings, even generals. Germs did not prevail in the Korean War; BW did not prove to be the decisive weapon as hoped against a determined foe with an apparently inexhaustible supply of soldiers to throw into the battle. BW is a distasteful weapon that casts moral reprehension upon all practitioners; it implies guile and effeminacy, and undermines the robust US military self-image enamored of air superiority, advanced technology, and overwhelming combat firepower. BW is an ugly closet skeleton which does not fit the image of “today’s army.”

Most likely, Truman was seduced into BW without thinking the whole project through.34  He knew nothing about the atomic bomb until he remarkably became president. This marvel of a weapon, created by nuclear physicists in deep secrecy in distant and exotic New Mexico, fell into his lap as the super device to dramatically and heroically end World War II. Germ warfare, an equivalent marvel, created by medical doctors in similar deep secrecy in distant and exotic Harbin, China must have felt like déjà vu. But as Truman learned, there is a big difference in military efficiency between killing 100,000 people instantly in a flash of nuclear fission, and trying to kill another 100,000 people slowly over several months by infectious disease. The other shortcoming Truman faced was that once he gave the approval, he had to rely on MacArthur’s, and later General Ridgeway’s, judgment concerning deployment, and he was stuck with the results.35

The first allegation of BW in March 1951 by Foreign Minister Pak, likely caught MacArthur and the Truman Administration flat-footed. They had not expected to be found out so quickly, and denial was their automatic first response. While conventional ordnance and napalm bombing continued unabated, there followed a year’s hiatus in BW deployments. When the second wave BW deployments began in 1952, Acheson was ready with the plausible denial defense. The Army was also ready with Sams’ plague ship in place at Wonsan Harbor and a large inventory of pathogens ready to be deployed. It was not a haphazard operation: it was a strategically planned and well-orchestrated bombing campaign over many months with many targets. It just did not produce the anticipated military results.

The subsequent cover-up was more successful than the germ deployment. The fact of its success is indicative of the rigorous compartmentalization within the military in which BW was operational. Only a handful of pilots and support personnel in the battle theater needed to know the payloads and targets. By insulating command in this manner, it would not have been difficult to subsequently purge the record. The common soldiers got their honorable discharges, their GI benefits, and were left alone. There was no incentive for any soldier to come forward with his germ story which would surely have landed him in deep trouble. The pilots’ complicity in war crime was also a very effective means of insuring their continued loyalty and silence after the war.

With the passage of time, the whole truth of America’s deployment of bio-weapons against North Korea and China during the Korean War is unlikely to ever be acknowledged unless there is some larger political desire to normalize relations with North Korea. The US has threatened and violently harassed North Korea on a continuous basis since the 1953 armistice with annual war games and enforced economic isolation. Current US officials claim North Korean behavior to be inexplicable and erratic, but few of these insiders are aware of America’s sordid and secret history, nor are they willing to acknowledge the complete destruction of North Korea and the death of one-third of its population due to American saturation bombings, or the fact that the US has never negotiated a permanent truce with North Korea, or paid war reparations for the horrific carnage. Academic deniers like Leitenberg will always be available to cast aspersions and sow doubt. However, since the Viet Nam war, most Americans have become highly skeptical of government pronouncements. There has been a general loss of faith in the honesty and reliability of politicians, governmental appointees, and professional authorities. Attempts by insiders to sanitize the past deserve to be met with disbelief and distain.


1. “Crime Against Humanity: With millions of civilian dead and homeless in Korea as a direct result of the deliberate US campaign of extermination, the latest American crime to come to light has been the launching of bacteriological warfare in Korea. Not content with the wiping out of entire cities and towns by napalm bombings, massacres of military and civilian prisoners, and campaigns such as ‘Operation Killer,’ the Americans have resorted to one more bestiality in their frantic efforts to conquer the Korean people and extend their aggression in Asia.” CMR, Vol. 122, No. 3, March 1952, 225.

2. The Review reported North Korean Foreign Minister Pak Hon-yeong’s (Bak Hong-yong) accusation to the United Nations of February 22, 1952 denouncing US use of biological warfare against North Korea. This was Pak’s second denunciation of US BW attacks. On May 8, 1951, he announced that the US had released plague pathogens in rural North Korean villages during a four-week window in December 1950 into January 1951. This was a defensive BW deployment to slow down the China’s Peoples Volunteer Army counter-invasion across the Yalu River to cover the UN forces’ hasty retreat from the Chinese border back to the 38th Parallel. Bak’s February 1952 announcement accused the US Army of dropping canisters containing plague- and smallpox-infested insects as offensive weapons on bombing sorties over North Korea in 1951-52. CMR, March 1952, 226. On March 8, 1952, China’s Foreign Minister, Chou En-Lai, announced that US planes flew 448 sorties over Northeast China over a six-day period from February 29 to March 5, 1952, and that canisters of germ-laden insects had been released during these raids. CMR, Vol. 122, No. 4, April, 1952, 317-20.

3. The subscription loss was due to US Postal Service embargo on US delivery which was the bulk of the Review’s circulation. The actual cause for the embargo was the Review’s publication of POW lists obtained from Chinese and North Korean military sources. The US Army policy during the war was not to release POW and MIA lists even though many families in the US were desperate to know the whereabouts of their husbands and sons.

4. For a concise history of the Powell-Schuman Sedition Trial, see Stanley Kutler, The American Inquisition: Justice and Injustice in the Cold War, Hill & Wang, New York, 1982.

5. Conversation with Doris Brin Walker, Powell’s defense attorney, February 2009.

6. A Bruise— Terror of the 731 Corps, a film by Haruko Yoshinaga, broadcast November 1976, Tokyo Broadcasting System. Yoshinaga succeeded in locating and interviewing twenty former members of Unit 731.

7. Sheldon Harris cites this lowball number in Factories of Death: Japanese Biological Warfare, 1932-1945, and the American Cover-up, Routledge, New York & London, 2002, 65. However, it is not known precisely how many victims died at Unit 731. The 3,000 figure comes from the interrogated Japanese scientists who had motives to greatly minimize their carnage. Most victims were Chinese soldiers, both Nationalists and Communists, Russian soldiers, and abducted local civilians. Japanese camp personnel destroyed laboratories, buildings and camp files when the facility was abandoned abruptly at war’s end. The corpses of experiment victims were routinely incinerated making quantification and individual identification of the dead impossible. The post-war interrogations of Unit 731 scientific personnel performed in Japan from 1945-47 by US Army Technical Intelligence – G2, War Dept. Intelligence Targets, and the Army Chemical Corps. remain classified and not available to FOIA requests. Peter Williams and David Wallace, Unit 731: The Japanese Army’s Secret of Secrets, Hodder & Stoughton, London, 1989, p 163.

8. John W. Powell, “Japan’s Biological Weapons, 1930-1945,” Bulletin of Atomic Scientists, Oct. 1981

9. “The Japanese BW experts …. not only infected their human guinea pigs with diseases to see how many would die, but on occasion—in pursuit of exact scientific information—made certain they did not survive. A group would be brought down with a disease and, as the infection developed, individuals would be selected out of the group and killed and autopsied so that the ravages of the disease could be ascertained at various time intervals.” John W. Powell, “Japan’s Germ Warfare; The US Cover-up of a War Crime,” Bulletin of Concerned Asian Scholars, Vol. 12, No.4, Oct-Dec 1980, 10.

10. Ibid., 3 and footnote 8.

11. “My recommendation is that we promise Naito [the intermediary] that no one involved in BW will be prosecuted as a war criminal.” This is Sanders’ recollection of his conversation with MacArthur, quoted in Williams and Wallace, Unit 731, 133. Sanders was quickly replaced by much more hard-nosed interrogators, Dr. Norbert Fell from Camp Detrick, and Col. Alva C. Carpenter, Legal Section Chief of the Army’s War Crimes Branch. Carpenter emerges as the central figure in the cover-up of Japanese BW war crimes. Williams and Wallace, Unit 731, Chap. 15.

12. The thesis that top US government officials, US War Crimes prosecutors, and Army High Command conspired to suppress public information about Japan’s BW campaign in Manchuria and elsewhere has been extensively documented by researchers in Japan, China, Russia and the West. That the US engaged in a cover-up to shield Dr. Ishii and his subordinates from war crimes prosecution in order to acquire Unit 731 research is now a broadly accepted conclusion. See: Powell, “Japan’s Germ Warfare” (n. 9); Williams and Wallace, Unit 731; Stephen Endicott and Edward Hagerman, The United States and Biological Warfare: Secrets from the Early Cold War and Korea, Indiana University Press, Bloomington, 1998; Harris, Factories of Death; Dave Chaddock, This Must Be the Place: How the U.S. Waged Germ Warfare in the Korean War and Denied It Ever Since, Bennett and Hastings Publishing, Seattle, 2013.       

13. In 1946, the Soviet Union was clamoring to interview Ishii and his staff, accusing Unit 731 of BW crimes. The Soviets claimed that captured American soldiers were also victims of BW experiments at Unit 731. The accusations were widely publicized around the world and in the US. The international outcry meant that the immunity deal for Ishii and his collaborators could only come from the very top. President Truman would necessarily have had to sign off, but in all likelihood the details were hammered out by Allen Dulles, Deputy Director of the recently chartered CIA. The Soviet prosecutors were refused access to Unit 731 scientists because the US counterclaimed that all the alleged victims of Unit 731 atrocities were Chinese nationals. The Soviets were denied standing.

14. Ken Alibek with Stephen Handelman, Biohazard; The Chilling True Story of the Largest Covert Biological Weapons Program in the World—Told from the Inside by the Man Who Ran It, Random House, New York, 1999, This is precisely Alibek’s thesis, that “Biopreparat,” the massive Soviet biological warfare program, was engaged in a Cold War BW arms race with the US.

15. It is estimated about 30,000 peasants in Siberia were murdered by Japanese BW bomb attacks in the decade 1935-45.

16. “As for developments during the Korean War, much of the US documentation on biological warfare at that time has been destroyed, is lost, is still classified, or has been painstakingly and more or less successfully laundered before being provided for public viewing…. We have documented that at least nineteen ‘secret’ category communications of 1952 between the Far East Command and the organization within the US responsible for biological warfare were pulled out of the Chemical Corps records before they were finally turned over to the US National Archives in 1969.” Endicott and Hagerman, The United States and Biological Warfare, 187-88.

17. While the total number of civilian and military casualties in the Korean War is not known, the vast bulk of death and destruction was caused by US military carpet bombing and napalm fire-bombing of North Korea and of Communist strongholds in mountainous South Korea. General Curtis LeMay stated, “We went over there and fought the war and eventually burned down every town in North Korea.”

18. Milton Leitenberg, “China’s False Allegations of the Use of Biological Weapons by the United States during the Korean War,” Woodrow Wilson Institute, March 25, 2016,

19. The authenticity of Leitenberg’s primary source is questionable. The Soviet dossier is just too pat and too convenient not to smell. The Politburo documents were obtained in an unknown manner by a Moscow-based reporter, Yasuo Naito, and published in Japanese translation by the newspaper, Sankei Shimbun. Leitenberg’s theory is therefore based on the English translations of the Japanese translation of presumably smuggled documents. “The circumstances under which these documents were obtained are unusual. Because the Presidential Archive does not allow researchers to make photocopies, the texts were copied by hand and subsequently retyped. We therefore do not have such tell-tale signs of authenticity as seals, stamps or signatures that a photocopy can provide. Furthermore, since the documents have not been formally released, we do not have their archival citations. Nor do we know the selection criteria of the person who collected them.” Kathryn Weathersby, “Deceiving the Deceivers: Moscow, Beijing, Pyongyang, and the Allegations of Bacterial Weapons Use in Korea,” Cold War International History Project Bulletin, Woodrow Wilson International Center for Scholars, Washington D.C., Winter 1998, Issue 11, 176

20. Historians Stephen Endicott and Edward Hagerman have undertaken a point-by-point rebuttal of Leitenberg’s earlier claims. “Comment on Milton Leitenberg’s article, ‘New Russian Evidence on the Korean War Biological Warfare Allegations: background and analysis’,” Cold War International History Project Bulletin, Woodrow Wilson Institute, No. 11, Winter 1988.

21. John Foster Dulles had publicly accused Truman of losing China to the Communists in 1949 by not sufficiently supporting the Nationalist Chang Kai-shek. However, Truman sent the Seventh Fleet to the Taiwan Strait to cover the Kuomintang Army retreat and to sever the island from China. Taiwan has been a US protectorate for the past 67 years.

22. “It was all very fishy. They were surprised and unhappy to see us. It was obvious that something suspicious was going on, and that it was a clandestine affair.” From an eye-witness account by a British soldier of an American Army special detachment dressed in “parkas” spreading chicken feathers into private homes in a North Korean village behind retreating UN Forces. The narrative is quoted at length in Williams and Wallace, Unit 731, 265-66. 

23. States with advanced BW capabilities include: Russia, China, North Korea, South Korea, Japan, India, Pakistan, Kazakhstan, Iran, Iraq, Israel, Syria, Libya, France, Italy, Germany, United Kingdom, Canada, Cuba, and the United States.

24. The effectiveness of the 1952 BW attack is still uncertain. The Chinese and North Korean civil and military authorities had time to prepare the urban and rural population in anticipation of the American BW attacks. Vigilance and the quick-response destruction of vectors were the main defense measures. It is also likely that the communists downplayed their losses to discourage the US Army about BW effectiveness. North Korean and Chinese leaders refused to permit International Red Cross observers to verify BW attacks, claiming the IRC was partisan and would report casualty figures, therefore allowing the US Army to better assess the results of the campaign.

25. Williams and Wallace, Unit 731, 263

26. This allegation was initially made in CMR, and was repeated in the opening defense argument of the Powell/Shuman trial. Quoted in Williams and Wallace, Unit 731, 260.

27. The question of whether Japanese scientists from Unit 731were employed on Sams’ plague ship is relevant because of the ISC findings. “In the light of all these and other similar facts, the Commission had no option but to conclude that the American Air Force was employing in Korea methods very similar to, if not exactly identical with, those employed to spread plague by the Japanese during the Second World War.” Report of the International Scientific Commission for the facts concerning Bacterial Warfare in Korea and China (ISC Report), Beijing, 1952, 27.

28. The ISC interviewed four captured American pilots in a North Korean POW camp. From a scientific point of view this made sense to the Commission members as the BW delivery protocol should be described with the highest accuracy possible. The four captured American pilots voluntarily revealed explicit information about delivery mechanics, BW operational logistics, and preflight briefings. Politically however, interviewing the American POW pilots would serve later as a pretext for US Government spokespersons to impugn the impartiality of the ISC investigation.

29. The results of brainwashing ascribed to the Chinese torturers, i.e., the insertion of false memories into the victim’s mind, have yet to be duplicated by modern neuroscience. However, this war-time rationale provided American officials a means to dismiss all 38 pilot confessions en masse without having to answer to any of the specific details within the confessions themselves. “Not only did ‘brain-washing’ account for the astounding confessions made by captured American flyboys but soon it would be used to explain a whole raft of mysterious events emanating from China, and even the dominant and characteristic features of behavior of the Chinese population itself.” Chaddock, This Must Be the Place, 45. Chaddock further examines the claims of POW torture by the Chinese and finds no corroborating evidence. To the contrary he uncovers many stories in local print media from returning POWs affirming that they had not suffered any physical abuse. “When former POW Bernie Smith returned to Memphis he was approached by two reporters seeking a story on ‘the tortures of a Communist prison.’ But Bernie took them by surprise. He said he had been treated very well. He could not oblige them with any atrocity stories at all. Bernie’s unexpected response brought him a number of threatening telephone calls and letters.” Milton Lowenberg, “‘Progressive’ POW,” The Nation, January 30, 1954, quoted in Chaddock, 122.

30. CMR, May 1952, 425-26.

31. “In the opinion of the Commission, therefore, there remains no doubt that a large number of voles suffering from plague were delivered to the district of Kan-Nan during the night of April 4th/5th, 1952 by aircraft which the villagers heard. This was identified as an American F82 double fuselage night fighter.” “The Kan-Nan Incident,” ISC Report (n. 27), 31. And again, “On the basis of the evidence presented, and on their own search and prolonged interrogations of a considerable number of witnesses, both medical and lay, the Commission was compelled to conclude that the delivery of various biological objects contaminated with anthrax bacilli to many places in the two Chinese provinces had taken place, and that this had given rise to a number of cases of mortal infection hitherto unknown in the region, namely pulmonary anthrax, and hemorrhagic meningitis. Eyewitness statements impossible to doubt indicated American planes as the vehicles of delivery of the infected objects.” “Incidents in Liotung and Liaohsi,” ibid., 36. The ISC report focused on five specific incidents of night-time aerial BW attacks in which there was significant evidence and eyewitness accounts to evaluate the truth of the allegation. Hundreds of reports were made in North Korea and China alleging BW attacks, and while some no doubt were the result of hysteria and fear of people on the ground, most were factual though not adequately documented. Finding and destroying infected vectors was the primary concern, not preserving evidence. The ISC report acknowledges the difficulty of establishing clear culpability in a BW attack, and sets out its methodology in “Incident Analysis Adopted by the Commission,” ibid., 15.

32. “An offensive biological program began in 1942 under the direction of a civilian agency, the War Reserve Service (WRS). The program included a research development facility at Camp Detrick, Maryland, testing sites in Mississippi and Utah, and a production facility in Terre Haute, Indiana. Experiments were conducted using pathogens including B. anthracis and Brucella suis.” George W. Christopher, et. al., “Biological Warfare: A Historical Perspective,” in Joshua Lederberg, ed., Biological Weapons: Limiting the Threat, MIT Press, Cambridge, MA, 1999, 22. Additionally, Ken Alibek, in his tell-all exposé on the Soviet Union’s BW program, Biohazard, claims to have co-authored a secret history of the parallel US and Soviet Cold War BW programs with veteran American bioweaponer, Bill Patrick. Alibek claims the Soviets had a high-level mole inside Fort Detrick that permitted them to stay abreast of US developments.

33. This is the research direction taken by Chaddock in his 2013 book This Must Be the Place.  The growing secrecy, perniciousness, and outright criminality within the upper ranks of American government beginning in the Cold War has also become a recent interest of scholars, e.g. David Talbot, The Devil’s Chessboard: Allen Dulles, the CIA, and the Rise of America’s Secret Government, HarperCollins, New York, 2015.

34. “By 1949, the US Joint Chiefs of Staff had biological warfare built into emergency war plans, and if the Berlin Blockade led to general war, they intended to use it. By 1951, after considerable discussion, a mature policy for first use if militarily advantageous was in place, with the Joint Chiefs placing biological warfare in the strategic category number one, with the same priority as atomic warfare. As far as the Joint Chiefs were concerned, biological weapons could be employed from the onset of war at the discretion of the president.” Endicott and Hagerman, The United States and Biological Warfare, 185-86.

35. Truman inherited the presidency 82 days into Roosevelt’s fourth term. He could have legally run for the office again in 1952 but chose not to. Instead he retired back to Missouri where he deliberately disappeared off the global stage. Very few individuals in history get the opportunity to order the murder of hundreds of thousands of people. It must have been very sobering.

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