The name was almost playful. Gerboise is the French word for jerboa, the long-legged desert rodent that springs across the Sahara's surface, and blue was the first color of the tricolor. There was nothing playful about the device. It was a plutonium implosion bomb, mounted on a tower at the Saharan Military Experiments Centre near Reggane, in the bleak plain of the Tanezrouft that the Tuareg name the land of thirst. France had been racing toward this moment for years, partly to restore the national prestige battered by the loss of empire, and the test came in the middle of the Algerian War for independence, on soil that Algerians would soon reclaim as their own.

The blast was felt far beyond the desert. Within days, Ghana froze all French assets in the country, declaring they would stay frozen until the effects of the explosion and any future tests became known. Morocco recalled its ambassador from Paris. Across a continent then shaking off colonial rule, a European power testing atomic weapons on African ground struck many as the old order in its most arrogant form. The diplomatic storm was real, but it was the physical fallout, drifting unseen on the desert wind, that would prove harder to answer for.

Fallout from the series was later detected as far away as Senegal, the Ivory Coast, Burkina Faso, and Sudan. When Algeria asked for an independent assessment, the International Atomic Energy Agency reported in the mid-2000s that the Gerboise Bleue site had the second-highest residual caesium-137 contamination of the four Reggane tests, though it judged the surface levels too low to require intervention or to endanger today's visitors and residents of Reggane. The dust has a long memory. In early 2021, Saharan sand blown north across the Mediterranean to France carried measurable, if harmless, traces of caesium-137 from these very tests, a quiet, ironic return of fallout to the country that produced it.

For decades, France treated the human cost of Reggane as a footnote. The official line held that the desert was empty and the doses negligible. The people who lived downwind told a different story, of cancers, of birth defects appearing years later, of villages that buried their dead and were never told why. In 2009 the French government finally agreed to compensate victims exposed by its tests in Algeria and French Polynesia, and to release more of the records. The acknowledgment came nearly half a century late, and for many of those who were children under that first mushroom cloud, far too late to matter.