Underground nuclear explosive detonated at Urta-Bulak gas field, Bukhara, Uzbekistan, 1966

In 1966, a nuclear explosive was detonated at Urta-bulak gas field in Southern Uzbekistan in order to extinguish a gas well fire that had been burning for almost three years and had resisted numerous attempts at control. The gas fountain, which formed at pressures of almost 300 atmospheres, had resulted in the loss of over 12 million cubic meters of gas per day through a 200 mm casing – enough to supply a city the size of St Petersburg. Two 445 mm holes were drilled that aimed to come as close as possible to the well at a depth of about 1500 meters in the middle of a 200 meters thick clay zone. One of these came to within about 35 m of the well and was used to emplace the special 30-kiloton charge which had been developed by the Arzamas weapons laboratory. Immediately after the explosion the fire went out and the well was sealed. This was the first of five PNEs used for this purpose, and all but one was completely successful in extinguishing the fire and sealing the well. No radioactivity above background levels was detected in subsequent surveys of any of the sites.