On May 1, 1962, near Ecker, 150 km north of Tamanrasset, there was an accidental venting of a French underground nuclear test. Due to improper sealing of the shaft, a spectacular flame burst through the concrete cap and radioactive gases and dust were vented into the atmosphere. The plume climbed up to 2600 m high and radiation was detected hundreds of kilometres away. About a hundred French soldiers and officials, including two ministers, were irradiated. The number of contaminated Algerians is unknown.