Lance Chemical Troopers have corrosive resistant shields. While most enemies with corrosive resistance ignore the elemental damage but take normal damage from the bullets that carried the effect, Chemical Troopers take almost no damage at all from corrosive guns. This is due to the Lance armor greatly reducing the bullet damage, and most elemental weapons are weak in that area. However, incendiary and shock weapons are still effective.
Badass Chemical Trooper
Badass Chemical Troopers can deploy a modified Scorpio Turret that fires corrosive projectiles. Badasses are significantly tougher than their standard counterparts, however the chemical tanks strapped to their backs present an additional vulnerability. Their backpacks, unlike the trooper, will sustain corrosive damage. The backpack gives off light green smoke when damaged and begins discharging a thick black and green smoke cloud when it is close to detonation. Destroying the pack will instantly kill the trooper wearing it regardless of the amount of damage dealt to the trooper himself. The number of hits seems to be more significant than the damage done by each shot when attacking the tank as with other Badass Troopers.