They could be two types of chemical uses the first would be soft which cause effects like slowing down you walking and draw speed, another soft could cause vision to blur. Hard chemicals would cause direct damage, either a slow build up of detrimental effect till death or constant damage.

Other area denail things could be naplam, planet side artilery strikes, and radition bombardment. These would kill you pretty quickly because a artilery shell blasting shrapnel though your body puts emphisis on massive internal hemoraging.

Another would be a costly put potent wide AoE EMP zone that shuts down equipment, recharge and electronic based equipment

Now, when I say chemical warfare, I don't necessarily mean poison gas.

Chemical warfare has always been used most effectively (on purpose) when it has been used for terrain denial. Usually when you don't have the means to deny the enemy access to the terrain using other means - lack of man power, terrain aspects, or time constraints don't allow-

Which means Dust doesn't need chemical weapons, specifically, in order to achieve what you propose.

Many things could do the same thing; such as, EVE's warp bubbles, a mine field, an un-shielded nuclear fuel rod, a constant artillery barrage, or a grenade that pulses a bubble and gives slow constant damage.

Chemical weapons are a little too WWI. This is the future. We have much funner ways of hurting each other. Be creative.

How about we get the other weapons working first.

Then after that, realize that you have given a small group of players the ability to block off or deny access to a large areas of the map which seems abit over powered to me.

This type of power is still being fought / cried over as we speak with no sign of letting up for just the current weapons in Dust.

The acronym KISS seems to fit here

Keep it simple stupid

atleast for now

what about a localized EMP that deactivates enemy shields (but not modules and other suit functions then it would be OP) in an area? I sorta like the Idea and perhaps a module that provides shielding from the blast?