Alfred "Al" Zeltmann was a member of the Special Engineer Detatchment (SED) at Los Alamos during the Manhattan Project.
Born in 1921, Zeltmann was raised in the Greenpoint neighborhood of Brooklyn, New York. He was working as a machinist and attending classes at Cooper Union when he was drafted into the Army in 1942.
Assigned to the SED, Zeltmann was briefly stationed at Oak Ridge before he arrived at Los Alamos in 1944. He served as a Technician Third Grade (T/3). He worked on detecting neutrons as part of the polonium production process for the "Fat Man" bomb's initiator. He then worked on the RaLa (radioactive lanthanum) experiments under Gerhart Friedlander.
After the war, Zeltmann remained at Los Alamos. He studied at the University of New Mexico, ultimately earning a Ph.D. in radiochemistry, and worked as a physical chemist at Los Alamos National Laboratory for nearly 40 years.