The outbreak at Ekaterinburg (then called Sverdlovsk), a town 900 miles east of Moscow, is one of the most secretive incidents in Soviet Cold War history. Medical records of all the victims were seized by the KGB, but the clues to what really happened appear in research material that two Russian scientists kept out of the hands of the Soviet authorities.
The Russians, working with American pathologists, have shown that many of the 68 people reported to have been killed in the outbreak of anthrax in April 1979 died from inhaling airborne spores of the deadly bacterium rather than from eating meat contaminated by anthrax, as the Soviet government suggested at the time. This conclusion was reached after the US-Russian research team analysed tissue samples from 42 of the victims, which had been preserved in paraffin blocks and kept by Dr Faina Abramova and Dr Lev Grinberg, two pathologists working in Sverdlovsk.
Although the Soviet security authorities removed the hospital records and autopsy reports, the scientists managed to save notes describing the appearance of the organs of 42 victims at the time of the autopsies.
From the tissue samples, the scientists concluded that the 42 victims had each inhaled at least 10,000 microscopic anthrax spores; these could only have come from biological warfare research because airborne spores do not occur naturally in such high concentrations. The Soviet authorities said the deaths were the result of a natural anthrax outbreak, and the official inquiry said the victims had lesions of the intestines, not the lungs.
The new research, published in the current issue of Proceedings of the National Academy of Sciences, confirms the account of a retired Soviet military intelligence officer, General Andrei Mironyuk, who said in 1991 that the deaths had been caused by the accidental release of anthrax from a secret laboratory at the nearby military Post No 19. The truth of this anecdotal account was confirmed last May when President Boris Yeltsin said that the outbreak had been caused by the release of a biological warfare agent.
The evidence produced by Drs Grinberg and Abramova, working with Olga Yampolskaya of the Botkin Hospital in Moscow and David Walker at the University of Texas, is consistent with the theories that either a biological weapon exploded or an accidental release occurred through the air filters of a research or manufacturing facility.
Anthrax, one of the deadliest bacterial infections of warm-blooded animals, is highly contagious. The bacteria cause high fever, convulsions, spleen enlargement, lesions of the lungs and rapid death. Military authorities in many countries, including Britain, have experimented with the bacterium as a biological warfare agent. During the Second World War, for instance, Britain exploded prototype anthrax bombs on Gruinard, an island off the west coast of Scotland; only recently, after extensive spraying with formaldehyde, a disinfectant, has the island been declared safe from anthrax spores, which can lie dormant in the soil for decades.
Alistair Hay, a chemical pathologist at Leeds University and expert on chemical and biological weapons, says research on the Sverdlovsk incident suggests a breach of the international weapons treaty. 'They should not have been working on anything with offensive implications. The research points to a military programme and raises a lot of suspicions. There seems to have been an extensive biological weapons research programme.'
Dr Walker says the tissue analysis clearly shows that the deaths were due to anthrax inhalation. Most of the deaths occurred within three or four days of exposure and 'there were some instances of people dying in the street'. The victims were downwind of the military installation. Respiratory anthrax is extremely rare, he says: just 11 cases have been reported since 1960. 'Here we have at least 42 in one outbreak. My understanding is, this couldn't have happened if the Soviet Union was conforming to the treaty. It's a smoking gun.'
The first details to emerge of the Sverdlovsk disaster appeared in January 1980 in Possev, a Russian-language magazine based in Frankfurt. The report, attributed to anonymous sources, said that an explosion at a military facility in the south-west of the city the previous April had showered civilians with a cloud of bacteria. Thirty to 40 cases of anthrax infection were reported each day for a month, it said, and the total number of deaths were estimated at more than 1,000. This was later shown to be an over- estimate, although about 1,000 people are thought to have suffered minor symptoms.
In March 1980, the United States embassy in Moscow requested an official explanation. A few days later, the Soviet authorities replied that, after a natural outbreak of anthrax in livestock, people had contracted intestinal anthrax by eating contaminated meat sold on the black market. The US government was sceptical: its intelligence sources put the outbreak down to a biological weapons accident. In 1987, Ronald Reagan said the Soviet account was 'inconsistent with the information available to us and, in many aspects . . . not consistent with a contaminated meat explanation'.
However, the Soviet authorites did manage to convince some US scientists, such as Professor Matthew Meselson, a biological weapons expert at Harvard University. After visiting the Soviet Union in 1986 and meeting Soviet scientists who had studied the outbreak, Professor Meselson wrote in 1988: 'Contrary to the US government version, there was no evidence of inhalatory anthrax. All epidemiological, clinical and patho-anatomical evidence supported the diagnosis of intestinal and cutaneous anthrax . . . It is clear that the United States version of the Sverdlovsk anthrax outbreak is in need of careful review.'
Now the latest research, which Professor Meselson helped to arrange, supports the US government's position. It appears that the gastrointestinal anthrax lesions resulted from the bacteria in the lungs spreading into the bloodstream.
Last year the Russian authorities suddenly allowed access to the scientists at Ekaterinburg. 'I suspect they (the authorities) thought we would not find anything out,' Dr Walker says. 'They had confiscated the autopsy reports, but had not removed the primary materials (the tissue
Dr Grinberg says the tissue samples taken in 1979 were not returned or shown to anybody 'because they constitute our intellectual property. I personally had no contacts with the security organisation about these materials. I had no contacts with the authorities about this work'.
If the KGB had contacted him, the outcome might have been very different, and we could still have been in the dark about what really happened that spring day in Sverdlovsk.