P3Y-294 was a planet visited by the rogue NID when they were operating from an offworld base (3.18 "Shades of Grey"). A team led by Col. Grieves visited the planet (5.10 "The Sentinel"). They stole a powerful beam weapon from the people there, and when three tried to stop them, Col. Grieves used the weapon on his pursuers, killing all three of them. The SGC returned the weapon to P3Y-294, but the government would have nothing more to do with Stargate Command.
When Col. Grieves was sent offworld to help SG-1 and SG-3 and SG-9 make the Sentinel work after another rogue NID mission caused problems on , General Hammond was concerned something similar may have occured.
--Aurora 08:42, 21 June 2006 (PDT)