After the war, the production facility was sold and converted to commercial pharmaceutical production. Research and development activities were continued. Japanese scientists in American custody who had participated in the Unit 731 program were granted amnesty on the condition that they would disclose information obtained during their program.
The program was expanded during the Korean War (1950-53). A new production facility incorporating adequate biosafety measures was constructed at Pine Bluff, Arkansas. Technical advances allowed large-scale fermentation, concentration, storage, and weaponization of microorganisms; production was begun in 1954. In addition, a program to develop countermeasures including vaccines, antisera, and theraputic agents to protect troops from possible biological attack was begun in 1953.
Volunteer studies were performed in a 1-million liter sphere at Fort Detrick known as the "eight-ball" to test weapons systems disseminating Francisella tularensis, Coxiella burnetti, and other pathogens. Animal experiments were conducted at Fort Detrick and at remote desert and Pacific sites.
Cities were unwittingly used as laboratories to test aerosolization and dispersal methods; Aspergillus fumigatus, B. subtilis var. globigii, and Serratia marcescens were used as simulants and released during experiments in New York City, San Francisco, and other sites. Concerns regarding potential public health hazards of simulant studies were raised after an outbreak of nosocomial S. marcescens (formerly Chromobacterium prodigiosum) urinary tract infections at Stanford University Hospital between September 1950 and February 1951, following covert experiments using S. marcescens as a simulant in San Francisco. A report from the Centers for Disease Control completed in 1977 found no association between reported morbidity and mortality from pneumonia and influenza and local simulant experiments.
A series of field tests took place under the auspices of the Biological Laboratories from 1943 to the mid-1960s:
There were 456 cases of occupational infections acquired at Fort Detrick during the offensive biological program, at a rate of less than 10 infections per million hours worked. The rate of occupational infection was well within the contemporary standards of the National Safety Council, and below the rates reported from other laboratories. There were three fatalities due to occupationally acquired infections; two cases of anthrax in 1951 and 1958, and a case of viral encephalitis in 1964. The mortality rate was lower than those of other contemporary surveys of laboratory-acquired infections. There were 48 occupational infections and no fatalities reported from production and testing sites. The safety program included the development and use of new vaccines as well as engineering safety measures.
Before 1969, when President Richard Nixon closed the American offensive biological warfare program, offensive agents were developed at the United States Army's biological-warfare laboratories at Fort Detrick, Maryland. These products, powdered spores and viruses, were loaded into bombs and other delivery systems stored at Pine Bluff, Arkansas. The 1969 budget for Chemical/Biological Warfare research was reported to be $300 million with $5 million for herbicides designed to kill food crops or strip trees of foliage to deprive enemy forces of ground cover.In 1977 the long-awaited volume, US Army Activities in the US Biological Warfare Program, was submitted to The Congress. It outlined in detail the entire BW research effort involving Camp and Fort Detrick, Dugway Proving Ground, Utah, Edgewood Arsenal, Md., Pine Bluff Arsenal, Ark., Rocky Mountain Arsenal, Colo. and numerous smaller testing sites around the Nation. The volumes noted the variety of weapons systems, but refrained from providing specifics because such information may still be used by the Nation's potential adversaries.
By the late 1960s, the United States had developed a biological arsenal which included numerous bacterial pathogens, toxins, and fungal plant pathogens that could be directed against crops to induce crop failure and famine.US Army Activities in the US Biological Warfare Program, Volume II reported, "Anticrop research at Fort Detrick concerned BW agents as well as CW (Chemical Warfare) agents, i.e. chemical herbicides and defoliants . . . Extensive field testing was done to assess the effectiveness of agents on crops. Many candidate anticrop BW agents were screened, resulting in five standardized BW anticrop agents. The 1977 report said the BW program included, " ... testing, production and stockpiling of anticrop agents. Between 1951 and 1969, 31 anticrop dissemination trials were conducted at 23 different locations. From 1951 until 1957, wheat stem rust spores and rye stem rust spores were produced and transshipped to Edgewood Arsenal ... where they were classified, dried and placed in storage. Between 1962 and 1969, wheat stem rust spores were produced, transshipped to Rocky Mountain Arsenal, Denver, Colorado, classified, dried and stored. The entire anticrop stockpile was destroyed as part of the biological warfare demilitarization program completed February 1973.
The Soviet Union, China, and North Korea accused the United States of using biological warfare against North Korea and China during the Korean War. However, there was no confirmation of these allegations, and no epidemiologic support to the North Korean claim of having experienced epidemics. The United States denied allegations and requested impartial investigations. The International Red Cross suggested the formation of a special commission to investigate, and the World Health Organization offered to intervene. However, neither China nor North Korea responded to the International Red Cross, and the World Health Organization’s offer was rebuffed as a disguised attempt of espionage. Although unsubstantiated, the accusations attracted wide attention and resulted in a loss of international good will toward the United States.Numerous unsubstantiated allegations were made during the Cold War era. These included a Soviet accusation that the United States had tested biological weapons against Canadian Eskimos, resulting in a plague epidemic, an allegation of United States plans to initiate a cholera epidemic in southeastern China, another Soviet accusation of a United States and Columbian biological attack on Columbian and Bolivian peasants. In July 1969 Great Britain submitted a proposal to the Committe on Disarmament of the United Nations prohibiting the development, production, and stockpiling of biological weapons, and providing for inspections in response to alleged violations. During the following September, the Warsaw Pact nations unexpectedly submitted a biological disarmament proposal similar to the British proposal, but without provisions for inspections. Subsequently, the 1972 Convention on the Prohibition of the Development, Production, and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on their Destruction was developed. The treaty was ratified in April, 1972, and went into effect in March of 1975. In anticipation of the 1972 Biological Weapons Convention, President Nixon terminated the United States offensive biological weapons program by executive order. The United States adopted a policy to never use biological weapons, including toxins, under any circumstances whatsoever. National Security Decisions 35 and 44, issued during November 1969 (microorganisms) and February 1970 (toxins), mandated the cessation of offensive biological research and production, and the destruction of the biological arsenal. Research efforts were directed exclusively to the development of defensive measures such as diagnostic tests, vaccines, and therapies for potential biological weapons threats. Stocks of pathogens and the entire biological arsenal were destroyed between May 1971 and February 1973 under the auspices of the US Department of Agriculture, the Department of Health, Education, and Welfare, and the Departments of Natural Resources of Arkansas, Colorado, and Maryland. Small quantities of some pathogens were retained at Fort Detrick to test the efficacy of investigational preventive measures and therapies. Factors influencing the decision to terminate the offensive biological program included pragmatic as well as moral and ethical considerations. Given the available conventional, chemical, and nuclear weapons, biological weapons were not considered essential for national security. The potential effects of biological weapons on military and civilian populations were still conjectural, and for obvious ethical and public health reasons, could not be empirically studied. Biological weapons were considered untried, unpredictable, and potentially hazardous for the users as well for those under attack. Field commanders and troops were unfamiliar with their use. In addition, the United States and allied countries had a strategic interest in outlawing biological weapons programs in order to prevent the proliferation of relatively low-cost weapons of mass destruction. By outlawing biological weapons, the arms race for weapons of mass destruction would be prohibitively expensive, given the expense of nuclear programs. After the termination of the offensive biological program, the US Army Medical Research Institute of Infectious Diseases (USAMRIID) was established in order to continue the development of medical defenses for US military members against potential biological attack. USAMRIID conducts research to develop strategies, products, information, and training programs for medical defense against potential biological weapons. Endemic or epidemic infectious diseases due to highly virulent pathogens requiring high-level containment for laboratory safety are also studied. USAMRIID is an open research institution; no research is classified. The in-house programs are complemented by contract programs with universities and other research institutions.