It was the single worst incident in a region of arid, mountainous western Kyrgyzstan, with a collection of shuttered Soviet-era uranium mining and processing sites, a legacy of extensive radioactive waste dumps, and a history of flooding and mudslides.
As of 2017, despite recent remediations funded by the World Bank and others, the treatment of radioactive waste at Mailuu-Suu still poses serious health and safety risks for local residents.
Operations left behind some 23 separate uranium tailings dams and 13 waste rock dumps,[5] poorly designed on unstable hillsides above a town of 20,000 people in an area prone to both landslides and earthquakes, holding a total 1,900,000 cubic metres (67,000,000 cu ft) of material containing radionuclides and heavy metals.
[6] On April 16, 1958, with mining and processing plants still operational, a combination of poor design, neglect, heavy rainfall and a reported earthquake caused the #7 tailings dam at Mailuu-Suu to fail.
[7] Lack of any public response by officials makes it difficult to identify fatalities from the April 1958 event, especially as distinguished from everyday exposure.