On 2 April 1979, spores of anthrax were accidentally released from a Soviet military research facility near the city of Sverdlovsk, Russia (now Yekaterinburg). The ensuing outbreak of the disease resulted in approximately 100 deaths, 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. All medical records of the victims were removed to hide serious violations of the Biological Weapons Convention that had come in effect in 1975. The accident is sometimes referred to as "biological Chernobyl".