Hanford, a railroad town beside the Columbia River, became the setting for a major conflict between congressional oversight and wartime secrecy. The enormous land seizures and plant construction there were part of the Manhattan Project, but Harry S. Truman’s inquiries brought him only partial knowledge: he learned the project’s essential purpose, yet the record gives no indication that he knew how plutonium was being separated or how the weapon would be made.

A hidden project and a vast land deal

For some time, investigators on the Truman Committee had been collecting hints of a secret enterprise larger than the Canol Project. Its unexplained expenditures appeared in fragments under the name Manhattan Project. On June 17, 1943, Truman telephoned Secretary of War Henry Stimson. Stimson told him that only a handful of people knew about the highly important development and asked him, in effect, to trust that it served a specific and unique purpose. Truman accepted that assurance without demanding further details.

The land acquisition at Hanford soon made the project harder to ignore. Lewis Schwellenbach, who had left the Senate to become a federal district judge in Spokane, contacted Truman about sudden condemnations for the DuPont Company along the Columbia River. Nearly half a million acres were involved. In a letter dated July 15, Truman reassured Schwellenbach that the land was being taken for a plant to make a secret weapon capable of a tremendous explosion, and expressed hope that it would work. The letter shows that Truman had learned more than Stimson had disclosed in their brief telephone call, but it does not establish that he knew the project’s technical methods.

Knowledge passed through ordinary channels

Truman’s letter was a serious security lapse. It carried sensitive information through the ordinary mail, in an offhand exchange with a former Senate colleague, rather than through a protected channel. More strikingly, Truman dictated it to Mildred Dryden; she therefore also learned that the plant was intended to produce a powerful secret weapon. The episode exposed a tension in Truman’s position: he had agreed not to press Stimson for details, but he was also sharing what he had learned in a routine written communication.

As far as the account establishes, the letter had no known public consequences. Neither Schwellenbach nor Dryden is reported to have disclosed its contents. The information did not, however, resolve the questions raised by Hanford’s scale. Senator Elbert Thomas of Oklahoma wanted the site investigated, and a Truman Committee staff member privately warned that complaints of waste and inefficiency there had become chronic. The staff member suspected that the War Department might be using secrecy, as it had in the Canol case, to conceal another serious failure. That was a suspicion, not a finding: the committee had not established that Hanford was wasteful.

An investigation checked by secrecy

On November 30, 1943, Truman told Thomas that he had sent an investigator to look into the matter and hoped to discover what was wrong. A few weeks later, Fred Canfil sent Truman a telegram from Walla Walla, Washington, after visiting the area. Canfil reported that Colonel Mathias, the DuPont plant’s commanding officer, had said Truman and Stimson had agreed that no member of Truman’s committee would enter the plant. Canfil also relayed information that War Department instructions had told Army officers and civilian engineers not to give information about the project to senators or anyone connected with the Senate.

The telegram made the restriction concrete: the issue was not simply that officials had declined to explain the project, but that instructions barred information from reaching congressional investigators. Canfil, who may not have known the plant’s purpose, had acted in the course of his duty. Truman considered him overzealous, noting that once Canfil learned he wanted something, he would not stop until it was done. Yet the result was not an expanded inquiry. After the telegram, committee interest cooled, and Truman again honored his understanding with Stimson.

The limits of what Hanford disclosed

The account distinguishes between knowing that Hanford was part of a secret weapons effort and understanding the work carried out there. It says there is no evidence Truman learned that plutonium was being separated from uranium-238 at Hanford, or knew how the projected explosion would be achieved. His July letter therefore disclosed the broad purpose, not the plant’s scientific process. That limit matters: the committee’s access to clues about the project did not amount to access to its technical work.

In February 1944, Stimson, General George Marshall, and Vannevar Bush went to the Capitol for a private briefing in Speaker Sam Rayburn’s office. The meeting disclosed the atomic-bomb program to congressional leaders for the first and only time on Capitol Hill, according to the account. Marshall described the bomb’s design, and Stimson explained the danger of Germany developing one first. The officials said they needed another $1.6 billion and asked that the money be provided without a trace showing how it was spent. Hanford thus stood within a project whose secrecy reached from a vast land condemnation and a guarded plant to the concealment of its funding. Its story records the boundary Truman tried to navigate: investigate possible waste, but stop where the wartime agreement required him to stop.