1980 Plesetsk launch pad disaster

The 1980 Plesetsk launch pad disaster was the explosion of a Vostok-2M rocket carrying a Tselina-D satellite during fueling at Site 43/4 of the Plesetsk Cosmodrome in the town of Mirny in the Soviet Union at 19:01 local time (16:01 UTC) on 18 March 1980, two hours and fifteen minutes before the intended launch time. Forty-four people were killed in the initial fire and four more soon died in the hospital from burns.

Source: Wikipedia — 1980 Plesetsk launch pad disaster (CC BY-SA 4.0)