Previously a limited-edition reward from participating in The Cicero Crisis, this mod can now be acquired as a drop by killing Corrupted Vor in level ≥40 Orokin Void missions.
Toxic Barrage is additive with similar mods. For example, a Strun with a max rank Toxic Barrage and Shotgun Savvy will have a 20% × (1 + 60% + 90%) = 50% status chance.