The old Irradiate has been removed from the game as a talent, and replaced with Toxic waste and has received a major buff. It also used to provide a significant boost to nuke damage, but this was removed as well.
All units within 7 range will take 20 damage every 0.9 game seconds. This debuff does not stack, so if a unit is in range of two Toxic Waste auras, only the first one to be applied will do damage. The damage can be increased up to +50 for each power cube picked up.
Megaman is a talent that increases the Toxic Waste range by +2, for a total of +9 range.
Having more than one toxic waste aura on a team is usually a waste of a perk, since the damage doesn't stack.
Toxic Waste also provides the unit with a life regen of 4, which is extremely powerful at low levels, especially when coupled with the debuff aura. However, after the first couple of minutes in the game, this life regeneration becomes un-noticeable. Frontline/Kiting heroes have other HP and/or shield regeneration that far surpass the life regeneration of 4, making toxic waste almost obsolete, even during the early-game stages.