In 1943, a young Julia Child was working for the CIA on a slightly different recipe than the ones we remember her for—a shark repellent that was soon spread widely through government agencies. There was just one problem: it didn’t keep the sharks away at all.

The CIA published documents from their archives, dating back to Child’s work on the WWII-era shark repellent project. At the time, Julia Child was Julia McWilliams and the CIA was the OSS (Office of Strategic Services)—and they were in search of a way to soothe fears of shark attacks as the ocean became more and more of a wartime front.

The solution, they hoped, would be a shark repellent, which is the task set before the Emergency Rescue Equipment’s Special Projects department where Child was employed. And eventually, the CIA notes, they department emerged with a “cake” recipe, this one however being made mostly of copper and dye:

According to several memos from mid-to-late 1943, bait tests showed copper acetate to be over 60% effective in deterring shark bites. Other field tests showed even more promising results. Unfortunately, the copper acetate was deemed completely ineffective in deterring attacks from the other carnivorous fish of concern to the Armed Forces: barracudas and piranhas. To create the repellent, copper acetate was mixed with black dye, which was then formed into a little disk-shaped “cake” that smelled like a dead shark when released into the water. These cakes could be stored in small 3-inch boxes with metal screens that allowed the repellent to be spread either manually or automatically when submerged in water. The box could be attached to a life jacket or belt, or strapped to a person’s leg or arm, and was said to keep sharks away for 6 to 7 hours.

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Unsurprisingly, a bit of copper acetate mixed with dye turned out not to be an absolute deterrent against a shark swimming by that they were hoping for. In fact, while it certainly didn’t seem to be attracting sharks, it didn’t seem to be turning them back either.

But, hey, figured the OSS, if we can’t actually repel sharks, maybe the next best thing is at least convincing everyone that we can. By then, news of the repellent had started to spread widely. It didn’t much matter that the repellent kept sharks away the same way that this stapler here on my desk, miles and miles from the nearest shore, is also managing to repel sharks right now (100% effectively, too—call me, R&D teams!). People wanted it, and they were getting it. It took more than 25 years before the product was finally discontinued.

Top image: Julia Child in later years, in her kitchen via University of Houston; Bottom image: 1943 OSS documents via CIA

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