P4S-161, a world of forests and grassy meadows, had been the site of a meeting of Rebel Jaffa leaders. It was also chosen as a target by operatives of the Trust who had begun a full-scale chemical attack against the Goa'uld and Jaffa by sending rockets carrying symbiote poison through the stargate to known Goa'uld worlds. Teal'c and M'zel arrived on the planet shortly after the attack and found every Jaffa, numbering in the thousands, had been killed instantly.
Cross Reference: M'zel, Rebel Jaffa, Symbiote Poison, Trust
Episode Reference: Endgame