VX 7 Nerve Gas

VX 7 nerve gas is a highly toxic nerve agent used by the UNSC. Proof that it was at least planned to be used in engagements with the Covenant can be seen on the small crates, labeled "VX - 7," scattered throughout Cairo Station and throughout New Mombasa and Old Mombasa in 2552, during The First Battle of Earth. It remains to be seen if the gas has any effect against Covenant soldiers due to biological differences.