It really happened in the 1960s. Called (for some reason) Project Dribble, the purpose was to give U.S. scientists experience in detecting underground nuclear tests in the Soviet Union. The first blast, a 5.3 kiloton bomb, took place in 1964 at the bottom of a 2,710-foot shaft 28 miles southwest of Hattiesburg and four miles northeast of Baxterville. The second bomb, much smaller, was exploded two years later within the cavity created by the first blast. (To be sure, these were only two of well over a thousand documented nuclear tests by the United States, with the vast majority taking place in Nevada.)

What's weird is that the first test (code-named "Salmon," by the way) took place in 1964 - the same year that Hattiesburg was also the Mississippi epicenter of Freedom Summer, a massive effort to educate and register African-American voters in the South. Unfortunately, I haven't been able to locate the exact date of the 1964 atomic explosion, so hold off for now about plots to irradiate Freedom Summer volunteers (what really happened, with cruder weapons, was bad enough).

(I first learned about the Mississippi atomic tests from "Places the United States Has Bombed," by artist/photographer elin o'hara slavick. Also check out her photos of the military community at Fayetteville, N.C., site of Fort Bragg -- some of her work on Fayetteville was featured in the "Missiles and Magnolias" issue of Southern Exposure.)