Harold A. Knapp photograph collection, 1950-1989

Harold Anthony Knapp was a scientist, mathematician, and activist who studied the effects of fallout from nuclear testing. Knapp was born in Berlin, New Hampshire and obtained his doctorate in mathematics, with a minor in physics, from the Massachusetts Institute of Technology in 1947. After working as an operations analyst for the Office of the Chief of Naval Operations, Knapp joined the United States Atomic Energy Commission in 1955, where he worked in the Fallout Studies Branch of the Division of Biology and Medicine. Dr. Knapp continued his career at the Institute for Defense Analyses from 1961 until 1981, and then worked at the Defense Communications Agency from 1981 until retiring in 1988. In 1988, he was awarded the Secretary of Defense Medal for Meritorious Civilian Service for his work on nuclear issues.

Dr. Knapp’s work on fallout led him to study the effect of radiation on sheep and cows in Utah and Nevada after an above-ground nuclear test in 1953. In 1963, he authored "Iodine-131 in Fresh Milk and Human Thyroids Following a Single Deposition of Nuclear Test Fallout,” a report on his work which found that human health was affected by the consumption of milk from livestock which had been exposed to fallout. The Atomic Energy Commission suppressed Knapp’s report, leading to his 1961 resignation. In 1979, amidst growing public concern about airborn nuclear fallout, Knapp produced a 620-page report on the subject using declassified research. Knapp continued to study fallout throughout his career and testified in trials as an expert witness for sheep ranchers and other citizens whose health was affected by nuclear testing. His work communicating the health impact of fallout received praise from Utah governor Scott Matheson and Stewart L. Udall, former Secretary of the Interior.

In addition to his professional work on fallout, in 1961 Knapp and his wife, Barbara Baldwin Knapp, became involved in advocating for James and John Giles and Joseph Johnson, three black Maryland men who were sentenced to death on false rape accusations. The Knapps conducted private investigations, published reports, and ran publicity for the three men. In 1967, the Giles brothers were freed after the state of Maryland confessed its error; in 1968, Johnson was pardoned by Governor Spiro Agnew. After this victory, the Knapps continued to advocate against the death penalty in Maryland and nationally. Knapp died on November 11, 1989, at the age of 65.