Dr. Meselson and his wife, the medical anthropologist Jeanne Guillemin, came to Yekaterinburg with other American experts for a painstaking study. They documented how a northeasterly wind on April 2, 1979, must have scattered as little as a few milligrams of anthrax spores accidentally released from the factory across a narrow zone extending at least 30 miles downwind.
“You can concoct a completely crazy story and make it plausible by the way you design it,” Dr. Meselson said, explaining why the Soviets had succeeded in dispelling suspicions about a lab leak.
In Sverdlovsk, as Yekaterinburg was known in Soviet times, those suspicions appeared as soon as people started falling mysteriously ill, according to interviews this month with residents who remember those days.
Raisa Smirnova, then a 32-year-old worker at a ceramics factory nearby, says she had friends at the mysterious compound who used their special privileges to help her procure otherwise hard-to-find oranges and canned meat. She also heard that there was some sort of secret work on germs being done there, and local rumors would attribute occasional disease outbreaks to the lab.