The Soviet peaceful nuclear explosions program -- formally "Nuclear Explosions for the National Economy," sometimes called Program 7 -- ran from 1965 to 1989 and comprised 156 nuclear tests using multiple devices across vast stretches of Soviet territory. Its American counterpart, Operation Plowshare, was modest by comparison. Led by weapons designer Alexander D. Zakharenkov, the Soviet effort quickly expanded from its initial focus on excavation and petroleum stimulation into six or seven application areas involving ten government ministries. The numbers tell the story of a bureaucratic appetite: 39 explosions for geological exploration, 25 to boost oil and gas output, 22 to create underground gas storage cavities, 5 to extinguish gas well fires, 4 to build canals and dams, and assorted others for mining, toxic waste storage, and research. The Ministry for Geology alone financed 51 detonations.

The gas well applications produced the program's most dramatic results. After the Urtabulak success, a 47-kiloton device sealed a blowout at the nearby Pamuk gas field in 1968. Two explosions at the Krestishche field in Ukraine followed in 1972, and in 1981 a 37.5-kiloton blast finally extinguished a fire at Kumzhinskoye in northern Russia that had burned for over a year. These successes were later cited as potential precedents during the 2010 Deepwater Horizon oil spill in the Gulf of Mexico -- though the idea was quickly dismissed by American officials. The excavation applications were more controversial. The Chagan test of January 15, 1965, in Kazakhstan created an artificial lake but also sent radioactivity drifting over Japan, drawing complaints from both the United States and Japan under the 1963 Partial Test Ban Treaty. The matter was quietly dropped, but the tension between the program's ambitions and its contamination risks was never resolved.

Not every detonation went as designed. The Kraton-3 explosion in Vilyuy, Yakutia, in 1978 was meant to unearth diamond-bearing ore. The diamonds proved insignificant. The plutonium contamination of local water supplies did not. According to anti-nuclear activist Alexei Yablokov, plutonium levels in the drinking water of the Vilyuy region measured ten thousand times above the maximum sanitary norm two decades after the blast. The Globus-1 test near the village of Galkino, 40 kilometers from Kineshma, was even more alarming. A small 2.5-kiloton underground detonation on September 19, 1971, part of a seismological survey for oil exploration, unexpectedly released radioactive gases through cracks in the earth. The contamination created a radioactive hot spot two kilometers across in a relatively populated area of European Russia. Worse, the nearby Shacha River, a tributary of the Volga, shifted course and threatened to flood the explosion site, raising the specter of nuclear pollution spreading through the entire Volga watershed. Engineers proposed a sarcophagus and a 12-kilometer diversion channel, but the costs were prohibitive. The site remains a quiet monument to miscalculation.

The last peaceful nuclear explosion, codenamed Rubin-1, was detonated in Arkhangelsk Oblast on September 6, 1988, as part of a geological seismic survey. Mikhail Gorbachev's disarmament initiative brought the program to a close at the end of that year, and the 1989 moratorium on nuclear testing at Soviet sites was applied to peaceful detonations as well. The program's legacy remains contested. Proponents argue it paid for itself many times over, saving the USSR billions of rubles and demonstrating technologies -- particularly for extinguishing gas well fires -- that have no viable non-nuclear alternative. Opponents, Yablokov foremost among them, counter that every peaceful nuclear application has a conventional substitute and that many of the detonations caused environmental disasters whose costs have never been fully tallied. The ground across dozens of Soviet-era test sites holds the answer, leaching it slowly into aquifers, rivers, and the long memory of the communities that live above.