Prerequisite: Alien
Environmental is a catch-all trait that means the alien can exist in strange or harsh environments. It could be that they are aquatic, and can exist just as well underwater as on land. They may be able to survive in the vacuum of space, endure the harsh heat of a volcanic world, the extreme cold of Volag- Noc or exist in the Vortex itself.
As a Minor Good Trait, the alien suffers no ill effects from one particular harsh condition. If it’s something like being able to survive underwater, their ability should be explained. Do they have gills, or can they store oxygen in some way?
As a Major Good Trait, the alien suffers no effects from any environment – for example, a Dalek can fly through space or drive along the bottom of the Thames. Again, there should be some rationalisation of this, such as the Dalek’s battle armour.