A spectacular explosion on Sunday night outside Tehran took place deep inside the Parchin military base, where Iran produces crucial elements of its missiles and other munitions, raising new questions about whether the blast was an accident or sabotage.
The explosion and resulting fire, which Iranian news organizations have described in only the most general terms, could be seen from apartments in Tehran and appeared to have destroyed several buildings. But it was distant from a part of the base to which the International Atomic Energy Agency has been seeking access for years, to investigate reports of experiments on high explosives that could have been used in nuclear weapons.
The agency’s evidence about that activity dates back more than a decade, and that part of the base has been so bulldozed and reconfigured in recent years that inspectors concede it is doubtful there is much left to see or test if they ever get access.
The explosion, according to satellite photographs from Airbus that were analyzed by the Institute for Science and International Security, took place in a densely built region toward the southern end of the base, in an area that appeared from past photographs to be littered with bunkers. The damage was reminiscent of pictures of a missile-development site 30 miles west of Tehran that was virtually destroyed during a test in November 2011 that killed 17 people, including Gen. Hassan Tehrani Moghaddam, the leading force behind Iran’s advanced missile efforts.
At that time, Israel was widely suspected of sabotaging the base. Yet there was never definitive evidence, and no group has ever taken responsibility. (A senior Israeli officer noted several weeks later that the timing of the explosion was remarkable because General Moghaddam, who traveled often, “just happened to be sitting in his office” at the time.)
By comparison, the damage at Parchin on Sunday night was not as extensive. Nor were the reported casualties, perhaps because the explosion happened in the evening, when presumably there were fewer workers in the area.
Iranian news media reports, while sketchy, indicated that two people were missing. The Institute for Science and International Security, in its study, concluded that “at least six buildings appear damaged or destroyed.” But vast parts of the base appeared untouched.