National Museum of Nuclear Science & History
Jose Romero was a staff worker at Los Alamos during the Manhattan Project.
Frei worked for Stone and Webster Engineering Corporation.
Seymour Calvert served for 11 months in the Special Engineering Detachment at Los Alamos. He specialized as a chemical engineer, and carried out experiments with beryllium that were often dangerous.
Hammond worked at the 300 Area at Hanford during the Manhattan Project.
