Quest:Mission: Eternal Flame

Objectives
Scout Knowles at the Ember Spear Tower has recommended that you use the Ever-burning Torches to destroy the four Plague Tanks surrounding Halgrind.
 * Southwest Plague Tank Destroyed
 * Northwest Plague Tank Destroyed
 * Northeast Plague Tank Destroyed
 * Southeast Plague Tank Destroyed

Description
The Forsaken are up to no good and from what I can tell, those plague tanks of sludge are a big part of it.

If I may suggest, , we should probably destroy them before they can get any more use out of the things. I took the liberty of preparing a bundle of torches from the Ember Clutch. These things have been burning for days!

Here, I'm sure you can put them to better use than I in destroying those tanks.

Rewards
You will also receive:

Completion
Nice!

But what's this about the stuff you found inside those tanks? Are you saying that the Forsaken are spraying a plague upon the vrykul down there?