The ISA developed Project Red Dust to be a high-explosive blast, low-radiation yield bomb designed to devastate an enemy city or fortification without irradiating the landscape to allow for easy capture and occupation of the ruins, and ISA clean up detachments would then clear of any harmful radioactivity.
During the Second Extrasolar War, General Dwight Stratson pushed for the use of the Red Dust nuclear weapons against the Helghast and halting their invasion of Vekta. The ISA Council, however, was very hesitant to utilize nuclear weapons, as they are seen as a taboo weapon, and the political consequences of possessing and using them on Vektan soil was too high. In reality, Stratson was eventually revealed to be a Helghast collaborator who planned on delivering the weapons to the Helghast under General Armin Metrac. Red Dust was transported to Helghan during the Helghast's retreat from Vekta. However, the Helghast were not able to secure the codes needed to detonate the device.
During the ISA invasion of Helghan in Operation Archangel, Batton joined Battle Group Mandrake to track down the nuclear weapons. The ISA have no knowledge of Red Dust's location, but believed their goal of capturing Scolar Visari would ensure in securing the weapons. Colonel Mael Radec attempted to extract the code from Batton following her capture in the Maelstra Barrens, but was unable to do so. An attack on the Battle Group over Pyrrhus followed, where Radec was able to secure the codes during the assault on the New Sun. Shortly afterwards, a Red Dust warhead was detonated in the city, destroying all of the ISA and Helghast forces fighting there, and severely weakening the ISA's hold on the planet.
The fallout from the Red Dust warhead contaminated large amounts of Petrusite, creating a more volatile form that were later harvested and used by Stahl Arms to develop new lethal weapons in the Helghast's arsenal.
- Interestingly, while the weapon does, in fact, generate radioactive fallout (as demonstrated by the existence of the irradiated Petrusite) none of the ISA troops fighting in and around the ruins of Pyrrhus seem to experience any radiation sickness or any other complications from the device's detonation. This was explained in Killzone: Mercenary, where Blackjack explained that massive amounts of radiation medicine were bought by the ISA, and the Helghast have a natural immunity to radiation. This explains the radiation however the nuclear weapon still had a very short half life between the initial detonation and the ISA retreat. This nuclear device was designed with the intent of using it to remove the Helghast army from southern Vekta, so it was likely designed to have a minimal long term gamma radiation fallout on an intended target.