The "Béryl incident" was a French nuclear test, conducted on May 1 1962, during which nine soldiers of the 621st Groupe d'Armes Spéciales unit were heavily contaminated by radiation. The test took place at In Ekker, Algeria, then a French department, and was designed as an underground shaft test.^[2] Due to improper sealing of the shaft, radioactive rock and dust were released into the atmosphere. The soldiers were exposed to as much as 600 mSv. As many as 100 additional personnel were exposed to lower levels of radiation, estimated at about 50 mSv, when the radioactive cloud produced by the blast passed over the command post, due to an unexpected change in wind direction. Among those exposed were several French government officials, including French Defence Minister Pierre Messmer and Gaston Palewski.

• http://en.wikipedia.org/wiki/Béryl incident