Nuclear labor issues the most dangerous tasks within the industry is intensified by nuclear secrecy. On May 22, 1986, a nuclear fuel reprocessing plant at La Hague in Normandy, sustained a mechanical malfunction. Five workers were exposed to unsafe levels of radiation and hospitalized. On April 12, 1987, the Tricastin Nuclear Power Plant fast breeder reactor coolant leaked contaminating seven workers. In July 2008, approximately 100 workers were exposed to a radiation leak. The Chernobyl nuclear reactor meltdown occurred on April 26, 1986, in the Ukraine, during a test of the Unit 4 reactor systems. The explosion and fire caused by human error
High-altitude nuclear explosion rads/day at four months after "Starfish" for a well-shielded satellite or manned capsule in a polar circular earth orbit, which caused NASA concern with regard to its manned space exploration programs. In general, nuclear effects in space (or very high altitudes) have a qualitatively different display. While an atmospheric nuclear explosion has a characteristic mushroom-shaped cloud, high-altitude and space explosions tend to manifest a spherical 'cloud,' reminiscent of other space-based explosions until distorted by Earth's magnetic field, and the charged particles resulting from the blast can cross hemispheres to create an auroral display which has led documentary maker Peter Kuran