Robert Blakeley with a refrigerator magnet bearing his creation, the design used to mark public fallout shelters at the height of the Cold War. (Bill Geerhart)

Robert Blakeley, whose yellow-and-black fallout shelter sign became a grim symbol of the Cold War and, in many places across the country, a now-rusting reminder of the perils of nuclear brinkmanship, died Oct. 25 at a senior-living community in Jacksonville, Fla. He was 95.

The cause was complications from a bacterial infection, said his daughter, Dot Carver.

Mr. Blakeley was a logistics official at the U.S. Army Corps of Engineers when he devised and perfected the shelter sign, an ominous image of three downward-pointing triangles that called to mind the international symbol for radiation and, in the event of a nuclear explosion, pointed toward the nearest public shelter.

The shelter system, created by newly elected President John F. Kennedy in 1961, was designed to safeguard millions of Americans in the event of a nuclear strike, offering a more substantial, concrete-walled means of protection than the oft-repeated suggestion to "duck and cover."

At the time, a strike seemed imminent, if not inevitable. A summer standoff with the Soviet Union over the control of Berlin placed U.S. military forces on high alert, and later in 1961, Life magazine ran a cover story showing a helmeted, plastic-gloved man in a “civilian fallout suit.” The story promised that “97 out of 100 people can be saved” from nuclear fallout if they take proper measures. Meanwhile, a 46-page civil defense pamphlet elaborated on the dark arts of “fallout protection.”

Mr. Blakeley’s sign at an intact Washington fallout shelter that opened in 1962. (Evelyn Hockstein/For The Washington Post)

That October, the first federally backed shelters were unveiled to the public. Located in the basements of churches, bank buildings, apartment complexes and municipal structures, the shelters were stocked with food and water and designed to prevent radiation exposure as well as the kind of mass chaos envisioned by television's "The Twilight Zone," where neighbors in one episode came to blows over access to a small private shelter.

Mr. Blakeley, a Marine veteran who served in two of the fiercest battles of World War II and the Korean War, was an expert on chaos but not graphic design. Still, he knew enough to dismiss an early suggestion that the signs be made of railroad board, a papery material that would be difficult to hang and likely go up in flames after an atomic blast.

"Whatever we developed," he told writer Bill Geerhart for a 2011 post on the Cold War blog Conelrad Adjacent, "it would have to be usable 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."

Mr. Blakeley enlisted Blair Inc., a design company based in Fairfax County, Va., to come up with a few options for the aluminum sign’s image. Blair was instructed to include at least one design inspired by the radiation symbol and to focus on crafting a straightforward, easily reproducible logo with room for directional arrows and details on a shelter’s capacity.

The results, Mr. Blakeley recalled, included a preliminary sketch of a family of three moving toward a shelter. There was also a distinctive triangular design that may have been drawn from Clarence P. Hornung’s “Handbook of Designs and Devices,” a commonly used reference work first published in 1932. The book featured a selection of triangle designs, including the one that Mr. Blakeley settled on while meeting with a visibly impatient Powell Pierpoint, the Army’s general counsel.

“I’m used to vacuum cleaner salesmen,” Mr. Blakeley recalled Pierpoint telling him. “What do you recommend?”

Mr. Blakeley’s choice, and subsequent development, proved fateful. Working with what is now the manufacturing company 3M, he settled on a durable form of reflective paint that has helped thousands of his signs remain visible (if faded) signifiers of shelters that have long gone out of use.

In time, the design Mr. Blakeley developed also became an instantly recognizable emblem of Cold War fear and uncertainly, visible in films and television shows as well as on concert posters and record covers, including Bob Dylan’s 1965 album “Bringing It All Back Home” and 1973 advertisements for the Who’s North American tour.

When asked about the legacy of his creation, Mr. Blakeley was nonchalant, treating the shelter signs as hardly more significant than his work as a president of Toastmasters International, the public-speaking organization.

When his children were young, he told Conelrad Adjacent, “we’d go down the street, and one of the kids would say, ‘Hey, Dad, there’s one of your signs.’ But you know, other than that it’s just like many of the other things that happen in life. It’s just one of those routine things. I don’t know if I’ve ever had an occasion to tell anybody that I was involved in it because I don’t think it’s ever been high on my priorities.”

Robert Wilson Blakeley was born in Ogden, Utah, 40 miles north of Salt Lake City, on Aug. 30, 1922. His parents ran a farm together, and his father also worked as a machinist at a nearby Air Force base.

Mr. Blakeley studied at Weber Junior College (now Weber State University) and Utah State University before enlisting in the Marines during World War II. He fought on the beaches of Iwo Jima. Later, called up from the reserves during the Korean War, he was one of the “Chosin Few” who escaped encirclement by overwhelming Chinese forces at the Chosin Reservoir.

A marriage to Jean Brown in the 1940s ended in divorce. He married Dorothy McArthur in 1952. She died in 1992. In 2003, Mr. Blakeley married Irene Davis.

In addition to his wife, of Jacksonville, survivors include a daughter from his second marriage, Dot Carver of Chantilly, Va.; three grandchildren; and four great-grandchildren. Robert Blakeley, a son from his second marriage, died in 1991.

Mr. Blakeley studied landscape architecture at the University of California at Berkeley and graduated in 1954. He also received a master’s degree in business administration, Carver said.

Mr. Blakeley worked for two years at the Veterans Administration before moving to the Washington area and joining the Corps of Engineers as a civilian. He joined Toastmasters after giving what he described as an unsuccessful presentation to corps leaders.

Mr. Blakeley helped change Toastmasters’ bylaws to allow women to become full members, and after being elected its international president in 1976 he traveled across Africa, Europe and the United States to expand the group’s reach. He remained with the Corps of Engineers until 1981, retiring as chief of administrative services.

Among his unfinished projects was a small fallout shelter in the family’s back yard in Alexandria, Va., his daughter said. Mr. Blakeley had drawn up the plans, but apple trees filled the space instead. The blast never came.