African American Scientists and Technicians of the Manhattan Project

Baker Explosion, Operation Crossroads, Bikini Atoll, July 25, 1946
Courtesy United States Department of Defense

The African American Scientists and Technicians of the Manhattan Project

The Manhattan Project, 1941-1946, was the largest scientific undertaking in the history of the United States to that point.  It began with a letter to President Franklin Roosevelt in August 1939, from a number of prominent physicists including Albert Einstein and Leo Szilard, which warned of Nazi Germany’s efforts to produce “extremely powerful bombs of a new type,” and urged the United States government to engage in research that would produce the weapon first.  The Roosevelt Administration heeded the warning and on October 9, 1941, President Roosevelt approved a crash research program to build an atomic bomb.  Four years later this program produced the world’s first atomic bombs.  They were dropped on Hiroshima and Nagasaki, Japan in August 1945, instantly killing over 110,000 people and forcing the Japanese government to surrender.  This display of deadly power, heretofore unmatched in the history of humankind, ushered in the nuclear age.

Approximately 130,000 Americans worked on the project with the vast majority, including a number of African Americans, serving as construction workers and plant operators at newly created communities such as Oak Ridge, Tennessee, Los Alamos, New Mexico, and Hanford, Washington.  Drawing on natural resources from around the world including critically important uranium from the Belgian Congo, scientists and technicians, plant operators, military personnel, and construction workers labored around the clock in secrecy to complete the project and build this weapon of mass destruction before Nazi Germany completed its own atomic bomb.  Much of the initial research on the U.S. bomb was done in existing laboratory facilities at major universities including Columbia, Princeton, and the largest of the atomic research centers, the Metallurgical Laboratory at the University of Chicago.

On August 13, 1942, the mission to produce the atomic bomb was officially named the Manhattan Engineer District in order to avoid calling attention to the scientific nature of the work.  The working title eventually became the Manhattan Project.  Several hundred scientists and technicians worked at various times and at numerous secret facilities across the United States and Canada that were engaged in the research that would produce the first atomic weapons.  Scientists such as Robert Oppenheimer, Enrico Fermi, and Edward Teller became legendary figures not only in the scientific community but among the general population when their crucial work on this project became generally known.   Only through the efforts of African American newspapers such as the Chicago Defender and the Pittsburgh Courier,  and after 1945 Ebony Magazine, however, were people made aware of the handful of black scientists and technicians (all men) who worked on the project as well.

The fact that any African American scientists and technicians were available to be involved in the Manhattan Project is remarkable given the enormous limitations placed on the education of blacks in the South before World War II.   As late as 1933 only 54% of Southern white students were attending high school and only 18% of Southern blacks were there at a time when the overwhelming majority of African Americans lived in the states of the former Confederacy.   Also given the huge differential in the laboratory equipment and prepared teaching staff, even those in segregated black high schools got scant exposure to any type of science training.   Students at historically black colleges at the time usually faced similar challenges.

Northern black students had greater opportunities for scientific training.  Thanks to the Great Migration that began in World War I and brought tens of thousands of blacks out of the South to Northern cities, a number of Southern born individuals, such as Moddie Daniel Taylor of Alabama and Jasper Brown Jeffries of North Carolina, were educated in Northern universities including the all important University of Chicago.  Northern-born African Americans such as Harold Delaney and Lloyd Quarterman, both of Philadelphia, although attending racially segregated schools in their hometown, nonetheless had far more exposure to science training than their Southern-born counterparts.

Not all of the scientists and technicians, however, overcame huge educational disadvantages to earn the right to work on the Manhattan Project.  Three black men, all of whom were classified as project scientists since they all had received Ph.D.’s before they were hired, had exceptionally stellar educations by any standard.   Chemist William Knox and his brother, biologist Lawrence Knox, were from a New Bedford, Massachusetts family that valued education.  Of the five siblings in that family, three men, William, Lawrence, and younger brother Clinton, who became an historian, all received Ph.D.’s before World War II.  William earned his Ph.D. from the Massachusetts Institute of Technology while Lawrence completed his doctorate at Harvard University.  Mathematics prodigy, J. Ernest Wilkins, born into a prominent black Chicago family, entered the University of Chicago in 1936 at the age of thirteen and received his Ph.D. in 1942 at the age of 19.

Although the black press described all of the African Americans working with the Manhattan Project as “white-coated scientists,” many were in fact technicians who nonetheless performed invaluable service in the development of the world’s first atomic weapons.  Lloyd Quarterman, whose official title was junior chemist, worked with Enrico Fermi at the University of Chicago and Albert Einstein at Columbia University.  Robert Johnson Omohundro was a mass spectroscopist which meant he identified and examined particles to calculate their mass.  After World War II four technicians, Harold Delaney, Ralph Gardner-Chavis, Jasper Brown Jeffries, and George Warren Reed, Jr., all completed their doctorates.   The training and contacts they gained while working on the Manhattan Project no doubt proved exceedingly valuable as they completed their advanced degrees.

When World War II ended the scientists and technicians moved on with their lives and work.  Some became faculty at black colleges and universities in the South.  Others pursued positions in private industry or returned to government employment.  Edwin Roberts Russell did all three.  He chaired the Division of Sciences at Allen University in South Carolina in the late 1940s and early 1950s, then worked for E.I. DuPont’s Savannah River Nuclear Laboratory which was a combined government-private industry project.   Samuel Proctor Massie, one of the Manhattan Project scientists, served as President of North Carolina Central College (now North Carolina Central University) between 1962 and 1966 until his appointment that year by President Lyndon Baines Johnson as the first African American faculty member at the U.S Naval Academy at Annapolis, Maryland.

Despite these individual success stories, the work of the black scientists and technicians on the Manhattan Project has been largely forgotten by most of those who lived during that era, and unknown to younger generations who are often encouraged to pursue careers in science, technology, engineering, and math (STEM) without knowing of those pioneers of color in that field nearly eight decades earlier.  We at have assembled the names of the individuals who worked on the Manhattan Project.   Their remarkable profiles are linked below.


Lawrence A. Knox
William Jacob Knox
Samuel Proctor Massie
Moddie Daniel Taylor
J. Ernest Wilkins


Sherman Carter
Harold Delaney
Harold Evans
Ralph Garner-Chavis
Jasper Brown Jeffries
Lloyd Albert Quarterman
Robert  Johnson Omohundro
George Warren Reed 
Edwin Roberts Russell
Benjamin Franklin Scott