Soviet Belarusian communist politician Andrei Gromyko, who served as Soviet foreign minister (1957–1985) and as Chairman of the Presidium of the Supreme Soviet (1985–1988), was responsible for many top decisions on Soviet foreign policy until he was replaced by Eduard Shevardnadze. In 1986, the Byelorussian SSR was contaminated with most (70%) of the nuclear fallout from the explosion at the Chernobyl power plant located 16 km beyond the border in the neighboring Ukrainian SSR.