Spores of anthrax were accidentally released from a military research facility near the city of Sverdlovsk, causing at least 68 deaths.

In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, fungi and protozoa. They were thought to have appeared as early as the mid-late Ordovician period as an adaptation of early land plants.

Anthrax is an infection caused by the bacterium Bacillus anthracis or Bacillus cereus biovar anthracis. Infection typically occurs by contact with the skin, inhalation, or intestinal absorption. Symptom onset occurs between one day and more than two months after the infection is contracted. The skin form presents with a small blister with surrounding swelling that often turns into a painless ulcer with a black center. The inhalation form presents with fever, chest pain, and shortness of breath. The intestinal form presents with diarrhea, abdominal pains, nausea, and vomiting.

On 2 April 1979, spores of Bacillus anthracis were accidentally released from a Soviet Armed Forces research facility in the city of Sverdlovsk in the Soviet Union. The ensuing outbreak of the disease resulted in the deaths of at least 68 people, although the exact number of victims remains unknown. The cause of the outbreak was denied for years by the Soviet authorities, which blamed the deaths on consumption of tainted meat from the area, and subcutaneous exposure due to butchers handling the tainted meat. The accident was the first major indication in the Western world that the Soviet Union had embarked upon an offensive programme aimed at the development and large-scale production of biological weapons.

Yekaterinburg, alternatively romanized as Ekaterinburg and formerly known as Sverdlovsk, is a city and the administrative centre of Sverdlovsk Oblast and the Ural Federal District, Russia. The city is located on the Iset River between the Volga-Ural region and Siberia, with a population of roughly 1.5 million residents, up to 2.2 million residents in the urban agglomeration. Yekaterinburg is the fourth-largest city in Russia, the largest city in the Ural Federal District, and one of Russia's main cultural and industrial centres. Yekaterinburg has been dubbed the "Third capital of Russia", as it is ranked third by the size of its economy, culture, transportation and tourism.