[4] He served in the Russian army in World War I, entering as a private soldier and rising to the rank of colonel of engineers.
[6] After his arrival in the US he established, with his brother Alexander, the Canadian Radium and Uranium Corp of New York[3] and became its president to sell the newly discovered rich ores in northern Canada, and later also in Colorado.
[5][7] George B. Pegram and his associates at Columbia University, who did some of the initial work on the Manhattan Project, sought Pregel's assistance because they did not have sufficient money to buy the uranium.
[8] In March 1945 the Canadian Foreign Exchange Control Board began formal hearings into Pregel's financial dealings.
Furthermore, Pregel agreed to terminate his agency agreement between Eldorado and the Canadian Radium & Uranium Corp.[9] He served as president and board chairman of the New York Academy of Sciences, as president of the French University (Ecole Libre) in New York, as trustee of the New School for Social Research and as vice-president of the American Geographical Society.