Underwater Breathing

From The 4400 Wiki, a fan encyclopedia that anyone can edit.

Underwater Breathing is a promicin-induced ability that allows its user to breath while underwater for an unlimited period of time. This ability is very rare and unique, as it physically manifests in the body as a series of fish-like gills on the user's back (which in turn make sure oxygen is in no short supply as it absorbs oxygen directly from the water itself). The ability can be deactivated by its user, to ensure the person can breath on land.

4400 Jung Pak has this ability.