Fritz Johann Hansgirg (18911949) was an Austrian electrochemist and metallurgist who in 1928 invented a carbothermic magnesium reduction process. In 1934, he left Austria for the Empire of Japan where he worked with industrialist Shitagau Noguchi to set up a magnesium plant, and then helped build a pilot plant to produce heavy water using a combined electrolysis catalytic exchange process he had invented. He moved to the United States in 1940, where he worked with industrialist Henry J. Kaiser to design a magnesium plant in California. In 1941, Hansgirg was arrested by the FBI on a presidential warrant and interned for "the duration of the war". After the war, the Soviet Union captured Hansgirgs plants in northern Korea, using the plants processes and equipment for their atomic bomb project.