Jeffrey Kaye
May 14, 2018 · 12 min read

Secret Report: US Military Approved Offensive Use of Biological Warfare on Enemy Agriculture in World War 2

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In the closing days of World War 2, the Joint Chiefs of Staff approved the offensive use of germ warfare aimed at destroying enemy crops, placing final approval at the discretion its top commanders in the field, according to Office of Strategic Services (OSS) documents formerly classified “Secret” and “Top Secret” held in the National Archives.

Actual approval by U.S. authorities for the offensive use of any type of biological warfare has never been published before. As we shall see, it was the practice of the U.S. government to only pass on such orders orally. Most likely this was because the orders involved actions widely deemed to be illegal.

Additional ink to full set of documents:

The purpose of plant biological warfare (BW), according to a Chemical Warfare Service document written soon after the war, was “to destroy or reduce the value of crop plants.” Practically, the practice amounted to a war crime. The intent was to deny food to enemy troops, increase hunger, if not produce famine among the population of combatant nations, and along with biological warfare against human targets, to sow panic and fear among civilian populations.

While it was known that the United States had by 1942 been developing a robust biological warfare capacity, no document had previously showed that any final approval for the use of germ warfare had been given.

During World War 2, responsibility for the BW program was placed in the War Department. In January 1944, the Secretary of War told the Chief of Staff of the Chemical Warfare Service (CWS), which was in charge of both chemical and biological warfare due to their supposed “similarity of action,” “the time has arrived that for military reasons work should be initiated for carrying on intensively the offensive as well as the defensive side of BW in preparation for protection against attack….”

In a July 1945 OSS “Secret” memo, written by Captain Donald B. Summers, CWS Chief, Special Assistants Division of the Research and Development Branch of the OSS, sent to his boss, Lt. Col. John M. Jeffries, Chief, Research and Development Branch, Summers stated:

It is understood that the Joint Chiefs of Staff have given their approval to the use of plant BW provided the theatre commander wishes to use it. In view of this attitude this division has planned several items which can make use of the material available from Chemical Warfare Service. This would necessitate the use of a machine shop and a carpenter shop. If desired this division will proceed with such investigations. Intelligence, both defensive and offensive, is being maintained on the other phases of BW.

OSS was the wartime predecessor of the CIA, responsible for organizing covert activities behind enemy lines, as well as gathering intelligence.

Among other items Captain Summers discussed in his report were the use of tablets that could kill or disable (“L” and “K” tablets, respectively), the use of marijuana (called “TD” in the report) in interrogations , and other intelligence technologies, such as silent weapons, secret writing, and toxic substances.

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From OSS Monthly Report, July 1945

Since the war in Europe had ended in early May 1945, it is presumed the “theatre commanders” with authority to use agricultural biological weapons referred to in the report were Pacific and Far Eastern commanders Admiral Chester Nimitz and General Douglas MacArthur.

Making crop-destroying agents “as virulent as possible”

It is known that during World War 2 the U.S. had developed pathogens to be used against plants and animals. This project was discussed in a now declassified 1947 report (PDF) from the Office of the Chief, Chemical Corps. Titled “Biological Warfare Research in the United States,” and written by U.S. Army Chemical Corps historian, Rexmond C. Cochrane, the report states, “Agents selected for investigation were made as virulent as possible, produced in special culture media and under optimum conditions for growth, and tested for virulence on animals or plants.”

The Chemical Corps history reported, “Biological studies in crop-destroying agents were suggested to the Chemical Warfare Service as early as March 1942, when it was reported that investigations of the agents of late blight of potatoes, rice fungus, wheat rusts, rubber leaf blight, and plant growth inhibitors might prove profitable.”

U.S. research on plant BW was centered at the Plant Research Branch, and later the Crop Research Division at Camp Detrick, Maryland. BW work, which had operated out of the Army’s Edgewood Arsensal, had shifted to the new Detrick facility in 1943. OSS indicated that the chemical materials described further on in this article, the province of its Special Assistants Division, continued to be stored, however, at Edgewood.

A much later U.S. Army report (PDF) in 1977 stated, “By the end of World War 2, a wide variety of disease agents effective against man, animals, and plants had been studied and limited field testing conducted.”

That report, which followed a spate of government scandals about covert operations that unfolded in the 1970s, informed its readers, “During World War 2, the policy of BW use implicitly paralleled the policy for Chemical Warfare (CW); that is, retaliation only.”

But the declassified OSS report shows that what was publicly admitted before was not truly the entire story.

A “Summary of Activities of Special Assistants Division,” attached to Capt. Summers’ report, also addressed to Lt. Col. Jeffries, and marked “Top Secret,” went into greater detail about the various OSS programs pertaining to biological warfare.

In his summary, Summers explained that his unit was kept informed regarding the latest developments in both enemy and allied biological warfare work through OSS’s Secret Intelligence, Research and Development and Counterintelligence (X-2) branches, as well as via the military’s Criminal Investigative Division, the CWS, and briefings from the Assistant to the Advisor to the Secretary of War.

OSS officials did not perform experiments themselves, but they had visited “areas where BW research and development was being performed and maintained contact with proper personnel.”

Summers told Jeffries that OSS had “[p]repared to use plant BW and obtained authorization for use.” [Bold emphasis added.] He also noted that OSS had “[p]repared plans for utilizing BW for OSS in case such a program was authorized.” Presumably in this latter instance he was talking about biological weapons to be used on humans.

Secret orders

A separate top secret memorandum, “Final Summary Report on BW,” written in September 1945, some months after the prior report, and after the end of hostilities with Japan, describes the covert nature of the authorities surrounding the BW program.

From the example quoted below, we can derive some insight into the nature of how orders were secretly provided for the germ warfare program at this time. It could also be considered an exemplar of how secret orders regarding biological warfare were communicated more generally, including possibly during the Korean War, when the U.S. was charged with a secret campaign of germ warfare against China and North Korea.

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From OSS Special Assistants Division, R&D, “Final Summary Report of BW,” Sept. 25, 1945

“There is no letter of authorization in the Special Assistants Division files” regarding the OSS participation in the biological warfare program, the report states for the record, “but it is understood from Major A. Gregg Noble, former Chief of Special Assistants Division, and from Captain Donald B. Summers, present Chief of Special Assistants Division that such authorization was given orally by Mr. Stanley P. Lovell, former Chief of Research and Development Branch and also by Lt. Colonel John M. Jeffries, present Chief of Research and Development Branch.”

The Final Summary Report also described the purpose of the BW program: “It was desired that OSS be aware of all possible developments both offensive and defensive made in the U.S. and in foreign countries and that Research and Development of OSS be in a position to recommend and made [sic] suitable BW devices should the opportunity present itself.”

The report concluded, “OSS could wage BW both against plants and animals in a relatively short time.” The context of the report also indicated that OSS was set to shut down at the end of 1945, and it was assumed that the Chemical Warfare Service would continue to run the BW operation during peacetime.

The report said, “tentative plans and devices were designed to include BW in the OSS scheme of activity.” While labeled “BW” agents, some of these items were really chemical agents such as defoliants.

Anti-crop agents: LN8, “feather bombs” and a “balloon gondola”

A 2015 review by Lawrence Roberge on the use of biological weapons on agriculture stated, “Biological weapons research in the United States during World War 2 included the development of anti-crop chemicals which were defoliants: 2,4-dicholorophenoxy acetic acid (2,4,-D) and 2,4,5-tricholorophenoxy acetic acid (2,4,5-T) [8,11]. Further research in anti-crop agents was directed at the fungal pathogens: P. infestans (Potato blight), Sclerotium rolfsii sacc (Sclerotium Rot of sugar beets), Piricularia oryzae Br. and Cav. (Rice blast), and Helminthosporium oryzae van Brede de Haan (Brown Spot of rice).”

According to Roberge, by the 1950s the U.S. was mass-producing plant pathogens, along with other forms of biological weaponry. By this time, the U.S. was developing a “feather bomb” and other anti-crop dispersal devices, including “large volume spray tanks to disperse dry anti-crop BW agents which could with one aircraft disperse a plant disease epidemic over an area in excess of 1,000 square kilometers.”

There were other dispersal devices as well, including “a balloon gondola which could under the proper weather conditions carry five containers of feather/fungal spores deep into enemy territory.”

These are very similar to devices used by Japan’s biological warfare division, Unit 731, and also to devices allegedly used by the United States against North Korea and China during the Korean War.

OSS use of plant BW included both actual biological agents and chemical agents. Two substances were codenamed “IR” and “E,” which were said to be “available in fairly large quantities.” According to the 1977 Army report referenced above, these substances were actually the pathogens Rice Blast and Brown Spot of rice, respectively.

Rice Blast is a fungus that destroys the leaves on rice, and has been responsible for famines in rice growing areas. Brown Spot is a disease that forms lesions on rice plants. Controversially, the Americans tested its use as a biological weapon in Okinawa in the 1960s.

But OSS felt that that when it came to anti-crop agents, a particular herbicide was deemed “most satisfactory.”

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Called LN8, the OSS rapporteur described it as a “white crystalline solid,” “very stable” and “1% soluble in water.” When applied, it could produce a “withering and yellowing” of leaves in one to three days.

“In a week to ten days the vegetation is completely stripped of its leaves,” the report stated, “the stalks fall over and the plant dies or fails to bear fruit.” Various methods of dispersal were discussed, including use of a DDT aerosol bomb with a delayed release (“a time pencil” in the OSS jargon).

Dow Chemical’s Special Projects Division manufactured LN8, according to a 2016 report by Joseph Trevithick at The National Interest.

“In April 1945, B-25 bombers with 550-gallon tanks in their bomb bays sped across test fields at Terre Haute, Indiana and Beaumont, Texas…. The Pentagon clearly envisioned a similar series of crop busting strikes,” Trevithick wrote.

The OSS report also discussed “possible BW devices for use against personnel.” One very lethal substance, called “X” in the report, “could be utilized in pills, pellets or powders that could be given in drink or spread on food.” It could also be put in “food stores or in water supplies.” Placed into “Carbowax,” the lethal substance could be put onto a “bullet, dart, or arrow.” Death would come via the shot itself or from a following infection. There was no antidote.

“The material maybe [sic] obtained from the Special Projects Division, CWS,” the report noted.

U.S. Use of Japan’s Unit 731 BW Experiments

In the 1952 report of the International Scientific Commission, headed by British scientist Joseph Needham, observers accused the United States of the use of plant biological warfare. In particular, packets of plant material dropped by U.S. planes were tested and found to contain various pathogens, including purple spot fungus, or Cercospora sojini Hara, which infects soybean crops; a species of Thecaphom, found on maize kernals, of a type never found in China or Korea before; and anthracnose (Glomerella), which infects a number of different plants, among other pathogens.

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Bacterial bombs designed along lines of Unit 731 germ bombs, ISC Report

Unknown to Needham and others investigating germ warfare charges during the Korean War, after World War 2, Gen. MacArthur, in conjunction with U.S. agencies, had helped negotiate a blanket amnesty with the leading members of Japan’s World War 2 biological warfare Unit 731, as part of a trade for the data gathered by the Japanese on illegal fatal BW human experiments on thousands of prisoners.

Needham and others had suspected that Unit 731’s leader, Shiro Ishii, and his associates, were involved in the biological warfare campaign they believed was used against both China and North Korea during the Korean War. Ishii and his co-workers had also worked on biological warfare agents aimed against plants.

According to historian Sheldon Harris, the main Unit 731 facility at Pingfan, Manchuria, “was equipped with several greenhouses that were used for plant BW experiments” (pg. 43). But the main operations were at Japan’s Unit 100 center, 20 square kilometers of experimental farms in the suburbs of Changchun, surrounded by 3-foot high electrical fences, where crops “would be subjected to experiments with various types of plant-killing bacteria” and different herbicides and pesticides (pg. 116).

By the end of World War 2, the U.S. was already aware of this research, although they did not know all the particulars at that point. According to a top secret annex to the Final Summary Report on BW discussed above, the Japanese were known to have developed use of pathogens (such as tylenchus tritici) to use against wheat, barley, rye and potatoes.

In an incredible admission, according to the OSS report, the U.S. was utilizing Japanese methods of germ warfare even before the end of the war, and prior to the amnesty deal worked out with Ishii and his associates.

Japan has “perhaps the best informed scientists in BW investigations of any nation in the world,” the report stated. “The Japanese investigations were extremely extensive and intensive so that some of the U.S. research utilized Japanese methods and techniques…. There is no evidence of mass production of these agents, although experimental secluded installations were known. Of course, the Japanese had no scruples hindering them, as U.S. has, from the use of these devices but no large scale operations were expected…. They did have an experimental bacterial bomb which has never been proved used.”

The first inkling of how massive the Japanese BW undertaking actually was came in the form of a report from the U.S. War Department’s Military Intelligence Service. Dated April 6, 1945, the report described how POWs had verified a Bacteriological Experimental Center commanded by Ishii in Harbin, China, according to the account given in Ed Regis’s book, The Biology of Doom: America’s Secret Germ Warfare Project (p. 85).

“Nature of the types of experiments being carried on here is extremely secret and their findings were never published for general assimilation,” the report stated.

It turned out that the U.S. underestimated the extent of Japan’s BW program at the end of World War 2. Over the next few years, various U.S. investigators would interrogate and debrief Japanese scientists, and got permission from Washington D.C. to provide amnesty to the Unit 731 war criminals to further the BW aims of U.S. researchers.

While there was an initial intent to end the U.S. BW program at the end of World War 2, those in charge of the program successfully lobbied to keep the research alive. Over the next years, the BW program at Ft. Detrick and associated centers would receive a massive influx of funding, and testing began anew.

The most controversial test of an operational BW program may have been that undertaken by the United States during the first two years of the Korean War. The U.S. strenuously denied North Korean, Russian, and Chinese charges of use of BW, either against humans or plants, and called for an “independent” investigation by the International Committee of the Red Cross or the UN’s World Health Organization.

But behind the scenes U.S. government authorities working under the auspices of the Psychological Strategy Board (PSB), staffed by top intelligence, military and State Department figures, were adamant the U.S. would never allow an independent investigation of use of biological weapons in Korea.

According to a memorandum of a PSB meeting in July 1953, the U.S. was opposed to an “actual investigation” that could expose Korean War military operations, “which, if revealed, could do us psychological as well as military damage.”

The memorandum specifically stated as an example of what could be revealed “8th Army preparations or operations (e.g. chemical warfare).” Given the history of how biological and chemical warfare techniques were admixed in U.S. usage, as we have seen above, it is not unfeasible that the document was coyly referring to U.S. use of biological weapons.

References: See “Final Summary Report on BW [Biological Warfare], from the Special Assistants Division, Research and Development Branch,” September 27, 1945, 7 pp., Records of the Office of Strategic Services (Record Group 226) 1940–1947, Entry 211, Box 20 of 45. Location: 250/64/32/1. CIA Accession: 85–0215R. Folder “G/6, Med Res. Lab #3”.

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