diff --git a/baystation12.dme b/baystation12.dme
index d11073692a8..64cd4dafe0b 100644
--- a/baystation12.dme
+++ b/baystation12.dme
@@ -481,6 +481,7 @@
 #include "code\game\objects\effects\aliens.dm"
 #include "code\game\objects\effects\anomalies.dm"
 #include "code\game\objects\effects\bump_teleporter.dm"
+#include "code\game\objects\effects\chemsmoke.dm"
 #include "code\game\objects\effects\effect_system.dm"
 #include "code\game\objects\effects\gibs.dm"
 #include "code\game\objects\effects\glowshroom.dm"
diff --git a/code/WorkInProgress/computer3/computer.dm b/code/WorkInProgress/computer3/computer.dm
index 2b70c3b6e59..f537341096c 100644
--- a/code/WorkInProgress/computer3/computer.dm
+++ b/code/WorkInProgress/computer3/computer.dm
@@ -191,7 +191,7 @@
 		for(var/x in verbs)
 			verbs -= x
 		set_broken()
-		var/datum/effect/effect/system/harmless_smoke_spread/smoke = new /datum/effect/effect/system/harmless_smoke_spread()
+		var/datum/effect/effect/system/smoke_spread/smoke = new /datum/effect/effect/system/smoke_spread()
 		smoke.set_up(5, 0, src)
 		smoke.start()
 		return
diff --git a/code/game/gamemodes/blob/blobs/factory.dm b/code/game/gamemodes/blob/blobs/factory.dm
index 35130546fcd..e197ff6dea8 100644
--- a/code/game/gamemodes/blob/blobs/factory.dm
+++ b/code/game/gamemodes/blob/blobs/factory.dm
@@ -103,7 +103,7 @@
 
 /mob/living/simple_animal/hostile/blobspore/Die()
 	// On death, create a small smoke of harmful gas (s-Acid)
-	var/datum/effect/effect/system/chem_smoke_spread/S = new
+	var/datum/effect/effect/system/smoke_spread/chem/S = new
 	var/turf/location = get_turf(src)
 
 	// Create the reagents to put into the air, s-acid is yellow and stings a little
diff --git a/code/game/gamemodes/wizard/artefact.dm b/code/game/gamemodes/wizard/artefact.dm
index 37b2de5a3ee..cf2ea1f487b 100644
--- a/code/game/gamemodes/wizard/artefact.dm
+++ b/code/game/gamemodes/wizard/artefact.dm
@@ -54,7 +54,7 @@
 			if(candidates.len)
 				src.used = 1
 				var/client/C = pick(candidates)
-				new /obj/effect/effect/harmless_smoke(H.loc)
+				new /obj/effect/effect/smoke(H.loc)
 				var/mob/living/carbon/human/M = new/mob/living/carbon/human(H.loc)
 				M.key = C.key
 				M << "<B>You are the [H.real_name]'s apprentice! You are bound by magic contract to follow their orders and help them in accomplishing their goals."
diff --git a/code/game/objects/effects/anomalies.dm b/code/game/objects/effects/anomalies.dm
index 4c2d0ae8fe0..8dca4ef26e1 100644
--- a/code/game/objects/effects/anomalies.dm
+++ b/code/game/objects/effects/anomalies.dm
@@ -27,7 +27,7 @@
 
 
 /obj/effect/anomaly/proc/anomalyNeutralize()
-	new /obj/effect/effect/bad_smoke(loc)
+	new /obj/effect/effect/smoke/bad(loc)
 
 	for(var/atom/movable/O in src)
 		O.loc = src.loc
diff --git a/code/game/objects/effects/chemsmoke.dm b/code/game/objects/effects/chemsmoke.dm
new file mode 100644
index 00000000000..ee78cb5d5bc
--- /dev/null
+++ b/code/game/objects/effects/chemsmoke.dm
@@ -0,0 +1,246 @@
+/////////////////////////////////////////////
+// Chem smoke
+/////////////////////////////////////////////
+/obj/effect/effect/smoke/chem
+	icon = 'icons/effects/chemsmoke.dmi'
+	opacity = 0
+	time_to_live = 300
+	pass_flags = PASSTABLE | PASSGRILLE | PASSGLASS		//PASSGLASS is fine here, it's just so the visual effect can "flow" around glass
+
+/obj/effect/effect/smoke/chem/New()
+	..()
+	var/datum/reagents/R = new/datum/reagents(500)
+	reagents = R
+	R.my_atom = src
+	return
+
+/datum/effect/effect/system/smoke_spread/chem
+	smoke_type = /obj/effect/effect/smoke/chem
+	var/obj/chemholder
+	var/range
+	var/list/targetTurfs
+	var/list/wallList
+	var/floorArea
+
+
+/datum/effect/effect/system/smoke_spread/chem/New()
+	..()
+	chemholder = new/obj()
+	var/datum/reagents/R = new/datum/reagents(500)
+	chemholder.reagents = R
+	R.my_atom = chemholder
+
+//------------------------------------------
+//Sets up the chem smoke effect
+//
+// Calculates the max range smoke can travel, then gets all turfs in that view range.
+// Culls the selected turfs to a (roughly) circle shape, then calls smokeFlow() to make
+// sure the smoke can actually path to the turfs. This culls any turfs it can't reach.
+//------------------------------------------
+/datum/effect/effect/system/smoke_spread/chem/set_up(var/datum/reagents/carry = null, n = 10, c = 0, loca, direct)
+	range = n * 0.3
+	cardinals = c
+	carry.copy_to(chemholder, carry.total_volume)
+
+	if(istype(loca, /turf/))
+		location = loca
+	else
+		location = get_turf(loca)
+
+	targetTurfs = new()
+
+	//build affected area list
+	for(var/turf/T in view(range, location))
+		//cull turfs to circle
+		if(cheap_pythag(T.x - location.x, T.y - location.y) <= range)
+			targetTurfs += T
+
+	//make secondary list for reagents that affect walls
+	if(chemholder.reagents.has_reagent("thermite") || chemholder.reagents.has_reagent("plantbgone"))
+		wallList = new()
+
+	//pathing check
+	smokeFlow(location, targetTurfs, wallList)
+
+	floorArea = targetTurfs.len
+
+	//Admin messaging
+	var/contained = ""
+	for(var/reagent in carry.reagent_list)
+		contained += " [reagent] "
+	if(contained)
+		contained = "\[[contained]\]"
+	var/area/A = get_area(location)
+
+	var/where = "[A.name] | [location.x], [location.y]"
+	var/whereLink = "<A HREF='?_src_=holder;adminplayerobservecoodjump=1;X=[location.x];Y=[location.y];Z=[location.z]'>[where]</a>"
+
+	if(carry.my_atom.fingerprintslast)
+		var/mob/M = get_mob_by_key(carry.my_atom.fingerprintslast)
+		var/more = ""
+		if(M)
+			more = "(<A HREF='?_src_=holder;adminmoreinfo=\ref[M]'>?</a>)"
+		message_admins("A chemical smoke reaction has taken place in ([whereLink])[contained]. Last associated key is [carry.my_atom.fingerprintslast][more].", 0, 1)
+		log_game("A chemical smoke reaction has taken place in ([where])[contained]. Last associated key is [carry.my_atom.fingerprintslast].")
+	else
+		message_admins("A chemical smoke reaction has taken place in ([whereLink]). No associated key.", 0, 1)
+		log_game("A chemical smoke reaction has taken place in ([where])[contained]. No associated key.")
+
+
+//------------------------------------------
+//Runs the chem smoke effect
+//
+// Spawns damage over time loop for each reagent held in the cloud.
+// Applies reagents to walls that affect walls (only thermite and plant-b-gone at the moment).
+// Also calculates target locations to spawn the visual smoke effect on, so the whole area
+// is covered fairly evenly.
+//------------------------------------------
+/datum/effect/effect/system/smoke_spread/chem/start()
+
+	//reagent application
+	if(chemholder.reagents.reagent_list.len)
+		for(var/datum/reagent/R in chemholder.reagents.reagent_list)
+			var/proba = 100
+			var/runs = 5
+
+			//dilute the reagents according to affected area
+			R.volume /= floorArea / 4
+			chemholder.reagents.update_total()
+
+			//apply wall affecting reagents to walls
+			if(R.id in list("thermite", "plantbgone"))
+				for(var/turf/T in wallList)
+					R.reaction_turf(T, R.volume)
+
+			//reagents that should be applied to turfs in a random pattern
+			if(R.id == "carbon")
+				proba = 75
+			else if(R.id in list("blood", "radium", "uranium"))
+				proba = 25
+
+			spawn(0)
+				for(var/i = 0, i < runs, i++)
+					for(var/turf/T in targetTurfs)
+						if(prob(proba))
+							R.reaction_turf(T, R.volume)
+						for(var/atom/A in T.contents)
+							if(istype(A, /obj/effect/effect/smoke/chem))	//skip the item if it is chem smoke
+								continue
+							else if(istype(A, /mob))
+								var/dist = cheap_pythag(T.x - location.x, T.y - location.y)
+								if(!dist)
+									dist = 1
+								R.reaction_mob(A, volume = R.volume / dist)
+							else if(istype(A, /obj))
+								R.reaction_obj(A, R.volume)
+					sleep(30)
+
+
+	//build smoke icon
+	var/color = mix_color_from_reagents(chemholder.reagents.reagent_list)
+	var/icon/I
+	if(color)
+		I = icon('icons/effects/chemsmoke.dmi')
+		I += color
+	else
+		I = icon('icons/effects/96x96.dmi', "smoke")
+
+
+	//distance between each smoke cloud
+	var/const/arcLength = 2.3559
+
+
+	//calculate positions for smoke coverage - then spawn smoke
+	for(var/i = 0, i < range, i++)
+		var/radius = i * 1.5
+		if(!radius)
+			spawn(0)
+				spawnSmoke(location, I, 1)
+			continue
+
+		var/offset = 0
+		var/points = round((radius * 2 * PI) / arcLength)
+		var/angle = round(ToDegrees(arcLength / radius), 1)
+
+		if(!IsInteger(radius))
+			offset = 45		//degrees
+
+		for(var/j = 0, j < points, j++)
+			var/a = (angle * j) + offset
+			var/x = round(radius * cos(a) + location.x, 1)
+			var/y = round(radius * sin(a) + location.y, 1)
+			var/turf/T = locate(x,y,location.z)
+			if(T in targetTurfs)
+				var/dist = cheap_pythag(T.x - location.x, T.y - location.y)
+				if(!dist)
+					dist = 1
+				spawn(0)
+					spawnSmoke(T, I, dist)
+
+//------------------------------------------
+// Randomizes and spawns the smoke effect.
+// Also handles deleting the smoke once the effect is finished.
+//------------------------------------------
+/datum/effect/effect/system/smoke_spread/chem/proc/spawnSmoke(var/turf/T, var/icon/I, var/dist = 1)
+	var/obj/effect/effect/smoke/chem/smoke = new(location)
+	chemholder.reagents.copy_to(smoke, chemholder.reagents.total_volume / dist, safety = 1)	//copy reagents to the smoke so mob/breathe() can handle inhaling the reagents
+	smoke.icon = I
+	smoke.layer = 6
+	smoke.dir = pick(cardinal)
+	smoke.pixel_x = -32 + rand(-8,8)
+	smoke.pixel_y = -32 + rand(-8,8)
+	walk_to(smoke, T)
+	smoke.opacity = 1		//switching opacity on after the smoke has spawned, and then
+	sleep(150+rand(0,20))	// turning it off before it is deleted results in cleaner
+	smoke.opacity = 0		// lighting and view range updates
+	fadeOut(smoke)
+	smoke.delete()
+
+//------------------------------------------
+// Fades out the smoke smoothly using it's alpha variable.
+//------------------------------------------
+/datum/effect/effect/system/smoke_spread/chem/proc/fadeOut(var/atom/A, var/frames = 16)
+	var/step = A.alpha / frames
+	for(var/i = 0, i < frames, i++)
+		A.alpha -= step
+		sleep(world.tick_lag)
+	return
+
+//------------------------------------------
+// Smoke pathfinder. Uses a flood fill method based on zones to
+// quickly check what turfs the smoke (airflow) can actually reach.
+//------------------------------------------
+/datum/effect/effect/system/smoke_spread/chem/proc/smokeFlow()
+
+	var/list/pending = new()
+	var/list/complete = new()
+
+	pending += location
+
+	while(pending.len)
+		for(var/turf/simulated/current in pending)
+			for(var/D in cardinal)
+				var/turf/simulated/target = get_step(current, D)
+
+				if(wallList)
+					if(istype(target, /turf/simulated/wall))
+						if(!(target in wallList))
+							wallList += target
+						continue
+				if(!target.zone)
+					continue
+				if(target in pending)
+					continue
+				if(target in complete)
+					continue
+				if(!(target in targetTurfs))
+					continue
+
+				pending += target
+
+			pending -= current
+			complete += current
+
+	targetTurfs = complete
+
+	return
\ No newline at end of file
diff --git a/code/game/objects/effects/effect_system.dm b/code/game/objects/effects/effect_system.dm
index 4273a5f8595..ab9885db166 100644
--- a/code/game/objects/effects/effect_system.dm
+++ b/code/game/objects/effects/effect_system.dm
@@ -236,7 +236,7 @@ steam.start() -- spawns the effect
 		delete()
 	return
 
-/obj/effect/effect/smoke/HasEntered(mob/living/carbon/M as mob )
+/obj/effect/effect/smoke/Crossed(mob/living/carbon/M as mob )
 	..()
 	if(istype(M))
 		affect(M)
@@ -382,116 +382,7 @@ steam.start() -- spawns the effect
 
 /datum/effect/effect/system/smoke_spread/mustard
 	smoke_type = /obj/effect/effect/smoke/mustard
-/////////////////////////////////////////////
-// Chem smoke
-/////////////////////////////////////////////
-/obj/effect/effect/smoke/chem
-	icon = 'icons/effects/chemsmoke.dmi'
 
-/obj/effect/effect/smoke/chem/New()
-	..()
-	var/datum/reagents/R = new/datum/reagents(500)
-	reagents = R
-	R.my_atom = src
-	return
-
-/obj/effect/effect/smoke/chem/Move()
-	..()
-	for(var/atom/A in view(2, src))
-		if(reagents.has_reagent("radium")||reagents.has_reagent("uranium")||reagents.has_reagent("carbon")||reagents.has_reagent("thermite"))//Prevents unholy radium spam by reducing the number of 'greenglows' down to something reasonable -Sieve
-			if(prob(5))
-				reagents.reaction(A)
-		else
-			reagents.reaction(A)
-
-	return
-
-/obj/effect/effect/smoke/chem/affect(mob/living/carbon/M as mob )
-	reagents.reaction(M)
-
-/datum/effect/effect/system/smoke_spread/chem
-	smoke_type = /obj/effect/effect/smoke/chem
-	var/obj/chemholder
-
-	New()
-		..()
-		chemholder = new/obj()
-		var/datum/reagents/R = new/datum/reagents(500)
-		chemholder.reagents = R
-		R.my_atom = chemholder
-
-	set_up(var/datum/reagents/carry = null, n = 5, c = 0, loca, direct, silent = 0)
-		if(n > 20)
-			n = 20
-		number = n
-		cardinals = c
-		carry.copy_to(chemholder, carry.total_volume)
-
-
-		if(istype(loca, /turf/))
-			location = loca
-		else
-			location = get_turf(loca)
-		if(direct)
-			direction = direct
-		if(!silent)
-			var/contained = ""
-			for(var/reagent in carry.reagent_list)
-				contained += " [reagent] "
-			if(contained)
-				contained = "\[[contained]\]"
-			var/area/A = get_area(location)
-
-			var/where = "[A.name] | [location.x], [location.y]"
-			var/whereLink = "<A HREF='?_src_=holder;adminplayerobservecoodjump=1;X=[location.x];Y=[location.y];Z=[location.z]'>[where]</a>"
-
-			if(carry.my_atom.fingerprintslast)
-				var/mob/M = get_mob_by_key(carry.my_atom.fingerprintslast)
-				var/more = ""
-				if(M)
-					more = "(<A HREF='?_src_=holder;adminmoreinfo=\ref[M]'>?</a>)"
-				message_admins("A chemical smoke reaction has taken place in ([whereLink])[contained]. Last associated key is [carry.my_atom.fingerprintslast][more].", 0, 1)
-				log_game("A chemical smoke reaction has taken place in ([where])[contained]. Last associated key is [carry.my_atom.fingerprintslast].")
-			else
-				message_admins("A chemical smoke reaction has taken place in ([whereLink]). No associated key.", 0, 1)
-				log_game("A chemical smoke reaction has taken place in ([where])[contained]. No associated key.")
-
-	start()
-		var/i = 0
-
-		var/color = mix_color_from_reagents(chemholder.reagents.reagent_list)
-
-		for(i=0, i<src.number, i++)
-			if(src.total_smoke > 20)
-				return
-			spawn(0)
-				if(holder)
-					src.location = get_turf(holder)
-				var/obj/effect/effect/smoke/chem/smoke = new /obj/effect/effect/smoke/chem(src.location)
-				src.total_smoke++
-				var/direction = src.direction
-				if(!direction)
-					if(src.cardinals)
-						direction = pick(cardinal)
-					else
-						direction = pick(alldirs)
-
-				if(chemholder.reagents.total_volume != 1) // can't split 1 very well
-					chemholder.reagents.copy_to(smoke, chemholder.reagents.total_volume / number) // copy reagents to each smoke, divide evenly
-
-				if(color)
-					smoke.icon += color // give the smoke color, if it has any to begin with
-				else
-					// if no color, just use the old smoke icon
-					smoke.icon = 'icons/effects/96x96.dmi'
-					smoke.icon_state = "smoke"
-
-				for(i=0, i<pick(0,1,1,1,2,2,2,3), i++)
-					sleep(10)
-					step(smoke,direction)
-				spawn(150+rand(10,30))
-					if(smoke) smoke.delete()
-					src.total_smoke--
 
 /////////////////////////////////////////////
 //////// Attach an Ion trail to any object, that spawns when it moves (like for the jetpack)
diff --git a/code/game/objects/items/weapons/alien_specific.dm b/code/game/objects/items/weapons/alien_specific.dm
index 7026cf6f74a..54348fe96c5 100644
--- a/code/game/objects/items/weapons/alien_specific.dm
+++ b/code/game/objects/items/weapons/alien_specific.dm
@@ -37,7 +37,7 @@
 			user << "<span class='notice'>\The [src] is full.</span>"
 			return
 	reagents.remove_reagent(25,"water")
-	var/datum/effect/effect/system/bad_smoke_spread/smoke = new /datum/effect/effect/system/bad_smoke_spread()
+	var/datum/effect/effect/system/smoke_spread/bad/smoke = new /datum/effect/effect/system/smoke_spread/bad()
 	smoke.set_up(5, 0, user.loc)
 	smoke.start()
 	playsound(user.loc, 'sound/effects/bamf.ogg', 50, 2)
diff --git a/code/modules/events/tgevents/vent_clog.dm b/code/modules/events/tgevents/vent_clog.dm
index d12631be36a..492b4480352 100755
--- a/code/modules/events/tgevents/vent_clog.dm
+++ b/code/modules/events/tgevents/vent_clog.dm
@@ -30,7 +30,7 @@
 		R.my_atom = vent
 		R.add_reagent(pick(gunk), 50)
 
-		var/datum/effect/effect/system/chem_smoke_spread/smoke = new
+		var/datum/effect/effect/system/smoke_spread/chem/smoke = new
 		smoke.set_up(R, rand(1, 2), 0, vent, 0, silent = 1)
 		playsound(vent.loc, 'sound/effects/smoke.ogg', 50, 1, -3)
 		smoke.start()
diff --git a/code/modules/mob/living/carbon/monkey/life.dm b/code/modules/mob/living/carbon/monkey/life.dm
index cd04a546dfd..6bb646771b0 100644
--- a/code/modules/mob/living/carbon/monkey/life.dm
+++ b/code/modules/mob/living/carbon/monkey/life.dm
@@ -250,22 +250,6 @@
 					var/breath_moles = environment.total_moles()*BREATH_PERCENTAGE
 					breath = loc.remove_air(breath_moles)
 
-					if(istype(wear_mask, /obj/item/clothing/mask/gas))
-						var/obj/item/clothing/mask/gas/G = wear_mask
-						var/datum/gas_mixture/filtered = new
-
-						filtered.copy_from(breath)
-						filtered.toxins *= G.gas_filter_strength
-						for(var/datum/gas/gas in filtered.trace_gases)
-							gas.moles *= G.gas_filter_strength
-						filtered.update_values()
-						loc.assume_air(filtered)
-
-						breath.toxins *= 1 - G.gas_filter_strength
-						for(var/datum/gas/gas in breath.trace_gases)
-							gas.moles *= 1 - G.gas_filter_strength
-						breath.update_values()
-
 					// Handle chem smoke effect  -- Doohl
 					var/block = 0
 					if(wear_mask)
diff --git a/code/modules/projectiles/guns/magic/wand.dm b/code/modules/projectiles/guns/magic/wand.dm
index c14e9f73f75..76e08259018 100644
--- a/code/modules/projectiles/guns/magic/wand.dm
+++ b/code/modules/projectiles/guns/magic/wand.dm
@@ -106,7 +106,7 @@
 
 /obj/item/weapon/gun/magic/wand/teleport/zap_self(mob/living/user as mob)
 	do_teleport(user, user, 10)
-	var/datum/effect/effect/system/harmless_smoke_spread/smoke = new /datum/effect/effect/system/harmless_smoke_spread()
+	var/datum/effect/effect/system/smoke_spread/smoke = new /datum/effect/effect/system/smoke_spread()
 	smoke.set_up(10, 0, user.loc)
 	smoke.start()
 	charges--
diff --git a/code/modules/projectiles/projectile/magic.dm b/code/modules/projectiles/projectile/magic.dm
index e2ce8735182..695794eece4 100644
--- a/code/modules/projectiles/projectile/magic.dm
+++ b/code/modules/projectiles/projectile/magic.dm
@@ -87,7 +87,7 @@
 		if(!stuff.anchored && stuff.loc)
 			teleammount++
 			do_teleport(stuff, stuff, 10)
-			var/datum/effect/effect/system/harmless_smoke_spread/smoke = new /datum/effect/effect/system/harmless_smoke_spread()
+			var/datum/effect/effect/system/smoke_spread/smoke = new /datum/effect/effect/system/smoke_spread()
 			smoke.set_up(max(round(10 - teleammount),1), 0, stuff.loc) //Smoke drops off if a lot of stuff is moved for the sake of sanity
 			smoke.start()
 
diff --git a/code/modules/reagents/Chemistry-Recipes.dm b/code/modules/reagents/Chemistry-Recipes.dm
index 6e51abec59c..8c227b1a589 100644
--- a/code/modules/reagents/Chemistry-Recipes.dm
+++ b/code/modules/reagents/Chemistry-Recipes.dm
@@ -454,8 +454,6 @@ datum
 				playsound(location, 'sound/effects/smoke.ogg', 50, 1, -3)
 				spawn(0)
 					S.start()
-					sleep(10)
-					S.start()
 				holder.clear_reagents()
 				return
 
diff --git a/code/modules/research/xenoarchaeology/machinery/coolant.dm b/code/modules/research/xenoarchaeology/machinery/coolant.dm
index bc03553bee0..6c0652f4084 100644
--- a/code/modules/research/xenoarchaeology/machinery/coolant.dm
+++ b/code/modules/research/xenoarchaeology/machinery/coolant.dm
@@ -37,7 +37,7 @@ datum/chemical_reaction/coolant
 	explode()
 
 /obj/structure/reagent_dispensers/coolanttank/proc/explode()
-	var/datum/effect/effect/system/harmless_smoke_spread/S = new /datum/effect/effect/system/harmless_smoke_spread
+	var/datum/effect/effect/system/smoke_spread/S = new /datum/effect/effect/system/smoke_spread
 	//S.attach(src)
 	S.set_up(5, 0, src.loc)
 
diff --git a/icons/effects/96x96.dmi b/icons/effects/96x96.dmi
index bc5d4929381..9deb1803262 100644
Binary files a/icons/effects/96x96.dmi and b/icons/effects/96x96.dmi differ
diff --git a/icons/effects/chemsmoke.dmi b/icons/effects/chemsmoke.dmi
index 5be1b638edd..4308e3d40bb 100644
Binary files a/icons/effects/chemsmoke.dmi and b/icons/effects/chemsmoke.dmi differ