In 1945, three terminally ill cancer patients at the University of Chicago's Billings Hospital were injected with a solution containing plutonium as part of a U.S. government research project involving 18 subjects. The research was made public by the Energy Research & Development Administration in 1976. A follow-up study found no evidence that the plutonium injections affected the health of the subjects or their pre-existing illnesses.

Sixteen days later on April 26, 1945, a second human plutonium injection took place at Billings Hospital in Chicago. A sixty-eight-year-old man, later identified as CHI-1, was injected with 6.5 micrograms of plutonium in the chemical form of the +6 citrate salt.

The Department of Energy released the medical records of 18 patients unknowingly injected with plutonium between 1945 and 1947 in one of the secret radiation experiments sponsored by the government during and after World War II. The 18 people were hospital patients who have since died.

During 1945 to 1947, 18 patients were injected with plutonium. These experiments were carried out by the Manhattan Project. The following hospitals were involved in the experiments. Manhattan District Hospital, Oak Ridge, Tennessee (1). Strong Memorial Hospital, Rochester, New York (11). Billings Hospital, University of Chicago (3).

Between April 1945 and July 1947, eighteen hospitalized patients at four medical institutions associated with the Manhattan Project were injected, without their informed consent, with measured doses of plutonium-238 or plutonium-239 in soluble citrate or other form. The hospitals included Strong Memorial Hospital in Rochester, the University of California Hospital in San Francisco, Billings Hospital at the University of Chicago, and the Manhattan District medical group at Oak Ridge.

All the available evidence suggests that none of the subjects injected with either plutonium or uranium at Rochester knew or consented to their being used as subjects in experiments from which they could not benefit.

During 1945 to 1947, 18 persons were injected with amounts of plutonium at the Manhattan Engineer District Hospital in Oak Ridge, TN (1 patient), at Strong Memorial Hospital in Rochester, NY (11 patients), at Billings Hospital of the University of Chicago (3 patients), and at the University Hospital of the University of California in San Francisco (3 patients).

Subsequently, between late April and late December of 1945, three cancer patients, code-named CHI-1, 2, and 3, were injected with plutonium. At least two and possibly all three were injected at the Billings Hospital of the University of Chicago.

At the dawn of the Atomic Age, 18 Americans were injected by the U.S. government with plutonium without their informed consent. The injections were given at Strong Memorial Hospital of the University of Rochester, Billings Hospital of the University of Chicago, the University of California Hospital in San Francisco, and the Manhattan Engineer District Hospital in Oak Ridge, Tenn.

It is most likely that the 30 experimental subjects were not made aware of the nature of the injections they received. In fact, records show that only one of the plutonium patients signed a consent form, which did not fully explain the medical procedure or risks. There is no documentation of consent for any other test subjects.

The next three injectees were patients suffering from cancer who had come into Billings Hospital in Chicago for treatment. From April through December, a man in his sixties suffering from lung cancer, a woman in her fifties suffering from breast cancer, and a young man suffering from Hodgkin's lymphoma were all injected.

The Advisory Committee’s ethical analysis states: "During the 1940s researchers in the United States injected plutonium into eighteen hospital patients without their informed consent." It further characterizes these as the "plutonium injection experiments" carried out at several hospitals, including Billings Hospital at the University of Chicago, focusing on the ethical harm caused by the lack of informed consent and secrecy surrounding the studies.

The government covered up most of these radiation mishaps until 1993, when President Bill Clinton ordered a change of policy and federal agencies then made available records dealing with human radiation experiments, as a result of Welsome's work. The resulting investigation was undertaken by the President's Advisory Committee on Human Radiation Experiments.

During 1945 and 1946, the first human injection experiments were performed on terminally ill patients at the University of Chicago and at other Manhattan Project-associated hospitals. The experiments were conducted to determine how rapidly plutonium was excreted and to support safety criteria for workers handling plutonium.

In its ethics volume, the Army Medical Department notes: "Like the Oak Ridge injection, the Chicago injections occurred without the consent of the individuals." This chapter on covert and deceptive American medical experimentation directly compares the plutonium injection at Oak Ridge with those at Chicago’s Billings Hospital, emphasizing that the Chicago patients did not consent to being injected with plutonium.

The ethics study reports: "None of the subjects was told what was being done, and none gave informed consent." Referring to the set of eighteen hospital patients injected with plutonium at various institutions including Billings Hospital in Chicago, it highlights that the subjects were not informed about the nature or purpose of the injections and did not provide informed consent.

The Wikipedia article on unethical human experimentation notes: "Dr. Joseph Gilbert Hamilton, a Manhattan Project doctor in charge of the human experiments in California, had Stevens injected with Pu-238 and Pu-239 without informed consent." In summarizing the wider program it adds: "Three patients at Billings Hospital at the University of Chicago were injected with plutonium," placing the Chicago injections within the broader context of non-consensual plutonium experiments.

The biographical entry on Albert Stevens states that he "was subjected to an involuntary human radiation experiment" and that on May 14, 1945, "he was injected with 131 kBq (3.55 μCi) of plutonium without his knowledge because it was erroneously believed that he had a terminal disease." It notes: "The first human plutonium injection experiments were approved in April 1945 for three tests: April 10 at the Manhattan Project Army Hospital in Oak Ridge, April 26 at Billings Hospital in Chicago, and May 14 at the University of California Hospital in San Francisco."

A course paper summarizing historical research explains: "On November 15, 1993, journalist Eileen Welsome of The Albuquerque Tribune published 'The Plutonium Experiment' describing how the United States Government had injected radioactive plutonium into unconsenting patients and listing five of those patient by name." This work helped expose that hospital patients, including those at Billings Hospital in Chicago, were used in plutonium injection experiments without consent.