Update with new test results:
- Consortium P12 Grenades
- Exo took 45 damage per tick
- Support, Assault and Stealth took 15 damage per tick
- Empire U23 Grenades
- Exo took 75 damage a tick
- Support, Assault and Stealth took 25 damage per tick
- Any character staying in the poison dies after ~10-15 seconds.
- Poison effect seems to last for about 2 seconds after leaving the cloud.
So as summary:
Against exos, poison grenades are a lot more effective than normal grenades due to the high loss of health per tick, however, against other classes, frag grenades should prove to be more effective since the opponent will most likely run from the cloud, so the total damage caused won't be as high.