In October 1964 the Atomic Energy Commission set off a 5.3-kiloton nuclear device 2,710 feet down in the Tatum Salt Dome, 21 miles southwest of Hattiesburg. The test, code-named Salmon, was part of Project Vela, which asked whether a country could hide an underground test by firing it in a salt cavity. A second, smaller shot, Sterling, followed in the cavity in December 1966, and two gas explosions were set off there in 1969 and 1970. These remain the only nuclear detonations east of the Mississippi River.
The cavity did muffle the shock, and Sterling's waves were about a hundred times weaker than in solid salt. Even so, the tests registered on seismographs as far away as Finland, so secret testing proved impossible. Residents felt overlooked and feared radiation. Schools closed and about four hundred people within two miles left their homes for the day, with adults paid $10 and children $5. Residents later reported property damage, dry wells and creeks gone black with silt. By 2015 the government had paid more than $16 million to residents and workers with health claims.
The Department of Energy cleaned up the surface by 1972 and still owns the subsurface, where it monitors wells; it has found no contamination at off-site sample points, and some remains near ground zero and at the detonation depth. Since 2010 the state has owned the surface as a forest and wildlife refuge. A granite marker and plaque stand among the test wells, and no digging or drilling is allowed without Department of Energy approval.
The closest stops worth working into your route
Roadside plaques and monuments within a short detour