CONELRAD recently posted a great piece that explores the origin of the famous fallout shelter sign that appeared across the country at the height of the Cold War. Worn and rusted, you can still see some of them today as lasting symbols of the atomic age.
The signs were the product of an almost palpable upswell of public survival-mania about whether or not family shelters were needed in American homes. Citizens and politicians were divided on the subject, fearful of neighbor turning against neighbor in the event of a Soviet nuclear attack. But soon, public shelters were to be designed for schools and buildings while existing ones from World War II had to be marked for reuse. Little thought was put into what signs these structures needed.
Robert W. Blakeley, a high-ranking civilian with the U.S. Army Corps of Engineers, was drafted into the National Fallout Shelter Program and tasked with figuring out what the necessary posters would look like. After several weeks of bull sessions, he and a Civil Defense liaison came to the conclusion that whatever they made, "it would have to be useable in downtown New York City, Manhattan, when all the lights are out and people are on the street and don't know where to go."
Therefore, the design needed to be bright—something you could see with the lighter American smokers would surely be carrying at the time—so yellow and black were chosen as the most eye-catching. And while there's some debate, the triple-triangle design, developed by graphic arts company Blair Inc., could have been inspired from a then-popular design manual:
"Hornung's Handbook of Designs & Devices" first published in 1932 and reprinted several times since. The book, a seminal graphics reference work widely used at the time, features a triangular design identical to the Fallout Shelter Sign symbol. In fact, when the sign was submitted for certification with the Judge Advocate General's (JAG) patent division this similarity did not go unnoticed by the government trademark attorneys... Not mentioned by the government attorneys in their memo is that an endnote in the 1946 edition of Hornung's book explains that the triangular shape arrangement seen in "Fig. 349" is a representation of "an ancient symbol for the Godhead."
Later, Blakeley and his teams presented the designs to the Special Assistant to the Secretary of the Army, Powell Pierpoint. When Pierpoint merely stated, "OK go with it," none of them could have imagined how large of a decision had just been made. [CONELRAD]