diff --git a/code/__DEFINES/atmospherics.dm b/code/__DEFINES/atmospherics.dm
index c6ca2cf0ec..c38f4d932e 100644
--- a/code/__DEFINES/atmospherics.dm
+++ b/code/__DEFINES/atmospherics.dm
@@ -175,4 +175,12 @@
 #define LAVALAND_EQUIPMENT_EFFECT_PRESSURE 50 //what pressure you have to be under to increase the effect of equipment meant for lavaland
 #define LAVALAND_DEFAULT_ATMOS "o2=14;n2=23;TEMP=300"
 
-#define THERMAL_ENERGY(gas) (gas.temperature * gas.heat_capacity())
\ No newline at end of file
+#define THERMAL_ENERGY(gas) (gas.temperature * gas.heat_capacity())
+
+#define ADD_GAS(gas_id, out_list)\
+	var/list/tmp_gaslist = GLOB.gaslist_cache[gas_id];\
+	out_list[gas_id] = tmp_gaslist.Copy();
+
+//ASSERT_GAS(gas_id, gas_mixture) - used to guarantee that the gas list for this id exists in gas_mixture.gases.
+//Must be used before adding to a gas. May be used before reading from a gas.
+#define ASSERT_GAS(gas_id, gas_mixture) if (!gas_mixture.gases[gas_id]) { ADD_GAS(gas_id, gas_mixture.gases) };
diff --git a/code/game/mecha/equipment/tools/other_tools.dm b/code/game/mecha/equipment/tools/other_tools.dm
index e22db80bb7..3eaddc14d2 100644
--- a/code/game/mecha/equipment/tools/other_tools.dm
+++ b/code/game/mecha/equipment/tools/other_tools.dm
@@ -426,7 +426,7 @@
 	if(!istype(T))
 		return
 	var/datum/gas_mixture/GM = new
-	GM.assert_gas("plasma")
+	ASSERT_GAS("plasma", GM)
 	if(prob(10))
 		GM.gases["plasma"][MOLES] += 100
 		GM.temperature = 1500+T0C //should be enough to start a fire
diff --git a/code/game/objects/effects/effect_system/effects_smoke.dm b/code/game/objects/effects/effect_system/effects_smoke.dm
index 3f32b18178..538ea3bd84 100644
--- a/code/game/objects/effects/effect_system/effects_smoke.dm
+++ b/code/game/objects/effects/effect_system/effects_smoke.dm
@@ -169,7 +169,7 @@
 				qdel(H)
 				var/list/G_gases = G.gases
 				if(G_gases["plasma"])
-					G.assert_gas("n2")
+					ASSERT_GAS("n2", G)
 					G_gases["n2"][MOLES] += (G_gases["plasma"][MOLES])
 					G_gases["plasma"][MOLES] = 0
 					G.garbage_collect()
diff --git a/code/game/objects/items/tanks/jetpack.dm b/code/game/objects/items/tanks/jetpack.dm
index 650da88240..65e37ed906 100644
--- a/code/game/objects/items/tanks/jetpack.dm
+++ b/code/game/objects/items/tanks/jetpack.dm
@@ -1,3 +1,4 @@
+<<<<<<< HEAD
 /obj/item/tank/jetpack
 	name = "jetpack (empty)"
 	desc = "A tank of compressed gas for use as propulsion in zero-gravity areas. Use with caution."
@@ -209,3 +210,216 @@
 		var/obj/item/clothing/suit/space/hardsuit/C = wear_suit
 		J = C.jetpack
 	return J
+=======
+/obj/item/tank/jetpack
+	name = "jetpack (empty)"
+	desc = "A tank of compressed gas for use as propulsion in zero-gravity areas. Use with caution."
+	icon_state = "jetpack"
+	item_state = "jetpack"
+	lefthand_file = 'icons/mob/inhands/equipment/jetpacks_lefthand.dmi'
+	righthand_file = 'icons/mob/inhands/equipment/jetpacks_righthand.dmi'
+	w_class = WEIGHT_CLASS_BULKY
+	distribute_pressure = ONE_ATMOSPHERE * O2STANDARD
+	actions_types = list(/datum/action/item_action/set_internals, /datum/action/item_action/toggle_jetpack, /datum/action/item_action/jetpack_stabilization)
+	var/gas_type = "o2"
+	var/on = FALSE
+	var/stabilizers = FALSE
+	var/full_speed = TRUE // If the jetpack will have a speedboost in space/nograv or not
+	var/datum/effect_system/trail_follow/ion/ion_trail
+
+/obj/item/tank/jetpack/New()
+	..()
+	if(gas_type)
+		ASSERT_GAS(gas_type,air_contents)
+		air_contents.gases[gas_type][MOLES] = (6 * ONE_ATMOSPHERE) * volume / (R_IDEAL_GAS_EQUATION * T20C)
+
+	ion_trail = new
+	ion_trail.set_up(src)
+
+/obj/item/tank/jetpack/ui_action_click(mob/user, action)
+	if(istype(action, /datum/action/item_action/toggle_jetpack))
+		cycle(user)
+	else if(istype(action, /datum/action/item_action/jetpack_stabilization))
+		if(on)
+			stabilizers = !stabilizers
+			to_chat(user, "<span class='notice'>You turn the jetpack stabilization [stabilizers ? "on" : "off"].</span>")
+	else
+		toggle_internals(user)
+
+
+/obj/item/tank/jetpack/proc/cycle(mob/user)
+	if(user.incapacitated())
+		return
+
+	if(!on)
+		turn_on()
+		to_chat(user, "<span class='notice'>You turn the jetpack on.</span>")
+	else
+		turn_off()
+		to_chat(user, "<span class='notice'>You turn the jetpack off.</span>")
+	for(var/X in actions)
+		var/datum/action/A = X
+		A.UpdateButtonIcon()
+
+
+/obj/item/tank/jetpack/proc/turn_on()
+	on = TRUE
+	icon_state = "[initial(icon_state)]-on"
+	ion_trail.start()
+
+/obj/item/tank/jetpack/proc/turn_off()
+	on = FALSE
+	stabilizers = FALSE
+	icon_state = initial(icon_state)
+	ion_trail.stop()
+
+/obj/item/tank/jetpack/proc/allow_thrust(num, mob/living/user)
+	if(!on)
+		return
+	if((num < 0.005 || air_contents.total_moles() < num))
+		turn_off()
+		return
+
+	var/datum/gas_mixture/removed = air_contents.remove(num)
+	if(removed.total_moles() < 0.005)
+		turn_off()
+		return
+
+	var/turf/T = get_turf(user)
+	T.assume_air(removed)
+
+	return 1
+
+/obj/item/tank/jetpack/suicide_act(mob/user)
+	if (istype(user, /mob/living/carbon/human/))
+		var/mob/living/carbon/human/H = user
+		H.forcesay("WHAT THE FUCK IS CARBON DIOXIDE?")
+		H.visible_message("<span class='suicide'>[user] is suffocating [user.p_them()]self with [src]! It looks like [user.p_they()] didn't read what that jetpack says!</span>")
+		return (OXYLOSS)
+	else
+		..()
+
+/obj/item/tank/jetpack/void
+	name = "void jetpack (oxygen)"
+	desc = "It works well in a void."
+	icon_state = "jetpack-void"
+	item_state =  "jetpack-void"
+
+/obj/item/tank/jetpack/oxygen
+	name = "jetpack (oxygen)"
+	desc = "A tank of compressed oxygen for use as propulsion in zero-gravity areas. Use with caution."
+	icon_state = "jetpack"
+	item_state = "jetpack"
+
+/obj/item/tank/jetpack/oxygen/harness
+	name = "jet harness (oxygen)"
+	desc = "A lightweight tactical harness, used by those who don't want to be weighed down by traditional jetpacks."
+	icon_state = "jetpack-mini"
+	item_state = "jetpack-mini"
+	volume = 40
+	throw_range = 7
+	w_class = WEIGHT_CLASS_NORMAL
+
+/obj/item/tank/jetpack/oxygen/captain
+	name = "\improper Captain's jetpack"
+	desc = "A compact, lightweight jetpack containing a high amount of compressed oxygen."
+	icon_state = "jetpack-captain"
+	item_state = "jetpack-captain"
+	w_class = WEIGHT_CLASS_NORMAL
+	volume = 90
+	resistance_flags = INDESTRUCTIBLE | LAVA_PROOF | FIRE_PROOF | ACID_PROOF //steal objective items are hard to destroy.
+
+/obj/item/tank/jetpack/oxygen/security
+	name = "security jetpack (oxygen)"
+	desc = "A tank of compressed oxygen for use as propulsion in zero-gravity areas by security forces."
+	icon_state = "jetpack-sec"
+	item_state = "jetpack-sec"
+
+/obj/item/tank/jetpack/carbondioxide
+	name = "jetpack (carbon dioxide)"
+	desc = "A tank of compressed carbon dioxide for use as propulsion in zero-gravity areas. Painted black to indicate that it should not be used as a source for internals."
+	icon_state = "jetpack-black"
+	item_state =  "jetpack-black"
+	distribute_pressure = 0
+	gas_type = "co2"
+
+
+/obj/item/tank/jetpack/suit
+	name = "hardsuit jetpack upgrade"
+	desc = "A modular, compact set of thrusters designed to integrate with a hardsuit. It is fueled by a tank inserted into the suit's storage compartment."
+	origin_tech = "materials=4;magnets=4;engineering=5"
+	icon_state = "jetpack-mining"
+	item_state = "jetpack-black"
+	w_class = WEIGHT_CLASS_NORMAL
+	actions_types = list(/datum/action/item_action/toggle_jetpack, /datum/action/item_action/jetpack_stabilization)
+	volume = 1
+	slot_flags = null
+	gas_type = null
+	full_speed = FALSE
+	var/datum/gas_mixture/temp_air_contents
+	var/obj/item/tank/internals/tank = null
+
+/obj/item/tank/jetpack/suit/New()
+	..()
+	STOP_PROCESSING(SSobj, src)
+	temp_air_contents = air_contents
+
+/obj/item/tank/jetpack/suit/attack_self()
+	return
+
+/obj/item/tank/jetpack/suit/cycle(mob/user)
+	if(!istype(loc, /obj/item/clothing/suit/space/hardsuit))
+		to_chat(user, "<span class='warning'>\The [src] must be connected to a hardsuit!</span>")
+		return
+
+	var/mob/living/carbon/human/H = user
+	if(!istype(H.s_store, /obj/item/tank/internals))
+		to_chat(user, "<span class='warning'>You need a tank in your suit storage!</span>")
+		return
+	..()
+
+/obj/item/tank/jetpack/suit/turn_on()
+	if(!istype(loc, /obj/item/clothing/suit/space/hardsuit) || !ishuman(loc.loc))
+		return
+	var/mob/living/carbon/human/H = loc.loc
+	tank = H.s_store
+	air_contents = tank.air_contents
+	START_PROCESSING(SSobj, src)
+	..()
+
+/obj/item/tank/jetpack/suit/turn_off()
+	tank = null
+	air_contents = temp_air_contents
+	STOP_PROCESSING(SSobj, src)
+	..()
+
+/obj/item/tank/jetpack/suit/process()
+	if(!istype(loc, /obj/item/clothing/suit/space/hardsuit) || !ishuman(loc.loc))
+		turn_off()
+		return
+	var/mob/living/carbon/human/H = loc.loc
+	if(!tank || tank != H.s_store)
+		turn_off()
+		return
+	..()
+
+
+//Return a jetpack that the mob can use
+//Back worn jetpacks, hardsuit internal packs, and so on.
+//Used in Process_Spacemove() and wherever you want to check for/get a jetpack
+
+/mob/proc/get_jetpack()
+	return
+
+/mob/living/carbon/get_jetpack()
+	var/obj/item/tank/jetpack/J = back
+	if(istype(J))
+		return J
+
+/mob/living/carbon/human/get_jetpack()
+	var/obj/item/tank/jetpack/J = ..()
+	if(!istype(J) && istype(wear_suit, /obj/item/clothing/suit/space/hardsuit))
+		var/obj/item/clothing/suit/space/hardsuit/C = wear_suit
+		J = C.jetpack
+	return J
+>>>>>>> 6b9832d... Merge pull request #31388 from vuonojenmustaturska/atmoscherrypicking
diff --git a/code/game/objects/items/tanks/tank_types.dm b/code/game/objects/items/tanks/tank_types.dm
index 9892c35445..146693dd05 100644
--- a/code/game/objects/items/tanks/tank_types.dm
+++ b/code/game/objects/items/tanks/tank_types.dm
@@ -21,7 +21,7 @@
 
 /obj/item/tank/internals/oxygen/New()
 	..()
-	air_contents.assert_gas("o2")
+	ASSERT_GAS("o2", air_contents)
 	air_contents.gases["o2"][MOLES] = (6*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C)
 	return
 
@@ -87,7 +87,7 @@
 
 /obj/item/tank/internals/plasma/New()
 	..()
-	air_contents.assert_gas("plasma")
+	ASSERT_GAS("plasma", air_contents)
 	air_contents.gases["plasma"][MOLES] = (3*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C)
 	return
 
@@ -105,8 +105,7 @@
 		return ..()
 
 /obj/item/tank/internals/plasma/full/New()
-	..()
-	air_contents.assert_gas("plasma")
+	..() // Plasma asserted in parent
 	air_contents.gases["plasma"][MOLES] = (10*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C)
 	return
 
@@ -125,13 +124,12 @@
 
 /obj/item/tank/internals/plasmaman/New()
 	..()
-	air_contents.assert_gas("plasma")
+	ASSERT_GAS("plasma", air_contents)
 	air_contents.gases["plasma"][MOLES] = (3*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C)
 	return
 
 /obj/item/tank/internals/plasmaman/full/New()
-	..()
-	air_contents.assert_gas("plasma")
+	..() // Plasma asserted in parent
 	air_contents.gases["plasma"][MOLES] = (10*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C)
 	return
 
@@ -145,8 +143,7 @@
 	w_class = WEIGHT_CLASS_SMALL //thanks i forgot this
 
 /obj/item/tank/internals/plasmaman/belt/full/New()
-	..()
-	air_contents.assert_gas("plasma")
+	..() // Plasma asserted in parent
 	air_contents.gases["plasma"][MOLES] = (10*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C)
 	return
 
@@ -169,7 +166,7 @@
 
 /obj/item/tank/internals/emergency_oxygen/New()
 	..()
-	air_contents.assert_gas("o2")
+	ASSERT_GAS("o2", air_contents)
 	air_contents.gases["o2"][MOLES] = (3*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C)
 	return
 
diff --git a/code/game/turfs/turf.dm b/code/game/turfs/turf.dm
index b02444281c..66406b88be 100755
--- a/code/game/turfs/turf.dm
+++ b/code/game/turfs/turf.dm
@@ -289,7 +289,7 @@
 			continue
 		var/list/S_gases = S.air.gases
 		for(var/id in S_gases)
-			total.assert_gas(id)
+			ASSERT_GAS(id, total)
 			total_gases[id][MOLES] += S_gases[id][MOLES]
 		total.temperature += S.air.temperature
 
diff --git a/code/modules/admin/verbs/debug.dm b/code/modules/admin/verbs/debug.dm
index cff80e6117..7fc6bc2e9f 100644
--- a/code/modules/admin/verbs/debug.dm
+++ b/code/modules/admin/verbs/debug.dm
@@ -715,7 +715,7 @@ GLOBAL_PROTECT(LastAdminCalledProc)
 		if(Rad.anchored)
 			if(!Rad.loaded_tank)
 				var/obj/item/tank/internals/plasma/Plasma = new/obj/item/tank/internals/plasma(Rad)
-				Plasma.air_contents.assert_gas("plasma")
+				ASSERT_GAS("plasma", Plasma.air_contents)
 				Plasma.air_contents.gases["plasma"][MOLES] = 70
 				Rad.drainratio = 0
 				Rad.loaded_tank = Plasma
diff --git a/code/modules/atmospherics/gasmixtures/gas_mixture.dm b/code/modules/atmospherics/gasmixtures/gas_mixture.dm
index ac8349f5f7..b9cba55ae6 100644
--- a/code/modules/atmospherics/gasmixtures/gas_mixture.dm
+++ b/code/modules/atmospherics/gasmixtures/gas_mixture.dm
@@ -21,10 +21,6 @@ GLOBAL_LIST_INIT(gaslist_cache, init_gaslist_cache())
 		cached_gas[ARCHIVE] = 0
 		cached_gas[GAS_META] = GLOB.meta_gas_info[id]
 
-#define GASLIST(id, out_list)\
-	var/list/tmp_gaslist = GLOB.gaslist_cache[id];\
-	out_list = tmp_gaslist.Copy();
-
 /datum/gas_mixture
 	var/list/gases
 	var/temperature //kelvins
@@ -43,30 +39,18 @@ GLOBAL_LIST_INIT(gaslist_cache, init_gaslist_cache())
 
 //listmos procs
 
-	//assert_gas(gas_id) - used to guarantee that the gas list for this id exists.
-	//Must be used before adding to a gas. May be used before reading from a gas.
-/datum/gas_mixture/proc/assert_gas(gas_id)
-	var/cached_gases = gases
-	if(cached_gases[gas_id])
-		return
-	GASLIST(gas_id, cached_gases[gas_id])
+// The following procs used to live here: thermal_energy(), assert_gas() and add_gas(). They have been moved into defines in code/__DEFINES/atmospherics.dm
 
-	//assert_gases(args) - shorthand for calling assert_gas() once for each gas type.
+	//assert_gases(args) - shorthand for calling ASSERT_GAS() once for each gas type.
 /datum/gas_mixture/proc/assert_gases()
 	for(var/id in args)
-		assert_gas(id)
-
-	//add_gas(gas_id) - similar to assert_gas(), but does not check for an existing
-		//gas list for this id. This can clobber existing gases.
-	//Used instead of assert_gas() when you know the gas does not exist. Faster than assert_gas().
-/datum/gas_mixture/proc/add_gas(gas_id)
-	GASLIST(gas_id, gases[gas_id])
+		ASSERT_GAS(id, src)
 
 	//add_gases(args) - shorthand for calling add_gas() once for each gas_type.
 /datum/gas_mixture/proc/add_gases()
 	var/cached_gases = gases
 	for(var/id in args)
-		GASLIST(id, cached_gases[id])
+		ADD_GAS(id, cached_gases)
 
 	//garbage_collect() - removes any gas list which is empty.
 	//If called with a list as an argument, only removes gas lists with IDs from that list.
@@ -80,6 +64,7 @@ GLOBAL_LIST_INIT(gaslist_cache, init_gaslist_cache())
 			cached_gases -= id
 
 	//PV = nRT
+
 /datum/gas_mixture/proc/heat_capacity() //joules per kelvin
 	var/list/cached_gases = gases
 	. = 0
@@ -195,7 +180,7 @@ GLOBAL_LIST_INIT(gaslist_cache, init_gaslist_cache())
 	var/list/giver_gases = giver.gases
 	//gas transfer
 	for(var/giver_id in giver_gases)
-		assert_gas(giver_id)
+		ASSERT_GAS(giver_id, src)
 		cached_gases[giver_id][MOLES] += giver_gases[giver_id][MOLES]
 
 	return 1
@@ -212,7 +197,7 @@ GLOBAL_LIST_INIT(gaslist_cache, init_gaslist_cache())
 
 	removed.temperature = temperature
 	for(var/id in cached_gases)
-		removed.add_gas(id)
+		ADD_GAS(id, removed.gases)
 		removed_gases[id][MOLES] = QUANTIZE((cached_gases[id][MOLES] / sum) * amount)
 		cached_gases[id][MOLES] -= removed_gases[id][MOLES]
 	garbage_collect()
@@ -230,7 +215,7 @@ GLOBAL_LIST_INIT(gaslist_cache, init_gaslist_cache())
 
 	removed.temperature = temperature
 	for(var/id in cached_gases)
-		removed.add_gas(id)
+		ADD_GAS(id, removed.gases)
 		removed_gases[id][MOLES] = QUANTIZE(cached_gases[id][MOLES] * ratio)
 		cached_gases[id][MOLES] -= removed_gases[id][MOLES]
 
@@ -245,18 +230,19 @@ GLOBAL_LIST_INIT(gaslist_cache, init_gaslist_cache())
 
 	copy.temperature = temperature
 	for(var/id in cached_gases)
-		copy.add_gas(id)
+		ADD_GAS(id, copy.gases)
 		copy_gases[id][MOLES] = cached_gases[id][MOLES]
 
 	return copy
 
+
 /datum/gas_mixture/copy_from(datum/gas_mixture/sample)
 	var/list/cached_gases = gases //accessing datum vars is slower than proc vars
 	var/list/sample_gases = sample.gases
 
 	temperature = sample.temperature
 	for(var/id in sample_gases)
-		assert_gas(id)
+		ASSERT_GAS(id,src)
 		cached_gases[id][MOLES] = sample_gases[id][MOLES]
 
 	//remove all gases not in the sample
@@ -282,7 +268,7 @@ GLOBAL_LIST_INIT(gaslist_cache, init_gaslist_cache())
 		gas -= "TEMP"
 	gases.Cut()
 	for(var/id in gas)
-		add_gas(id)
+		ADD_GAS(id, gases)
 		gases[id][MOLES] = text2num(gas[id])
 	return 1
 
@@ -310,10 +296,9 @@ GLOBAL_LIST_INIT(gaslist_cache, init_gaslist_cache())
 
 	//GAS TRANSFER
 	for(var/id in sharer_gases - cached_gases) // create gases not in our cache
-		add_gas(id)
+		ADD_GAS(id, gases)
 	for(var/id in cached_gases) // transfer gases
-		if(!sharer_gases[id]) //checking here prevents an uneeded proc call if the check fails.
-			sharer.add_gas(id)
+		ASSERT_GAS(id, sharer)
 
 		var/gas = cached_gases[id]
 		var/sharergas = sharer_gases[id]
diff --git a/code/modules/atmospherics/gasmixtures/immutable_mixtures.dm b/code/modules/atmospherics/gasmixtures/immutable_mixtures.dm
index 086e21daca..50e1b38e52 100644
--- a/code/modules/atmospherics/gasmixtures/immutable_mixtures.dm
+++ b/code/modules/atmospherics/gasmixtures/immutable_mixtures.dm
@@ -69,7 +69,7 @@
 
 /datum/gas_mixture/immutable/cloner/garbage_collect()
 	..()
-	add_gas("n2")
+	ADD_GAS("n2", gases)
 	gases["n2"][MOLES] = MOLES_O2STANDARD + MOLES_N2STANDARD
 
 /datum/gas_mixture/immutable/cloner/heat_capacity()
diff --git a/code/modules/atmospherics/gasmixtures/reactions.dm b/code/modules/atmospherics/gasmixtures/reactions.dm
index abbfcf8924..c466213409 100644
--- a/code/modules/atmospherics/gasmixtures/reactions.dm
+++ b/code/modules/atmospherics/gasmixtures/reactions.dm
@@ -57,7 +57,7 @@
 	cached_gases["co2"][MOLES] -= reaction_rate
 	cached_gases["agent_b"][MOLES] -= reaction_rate*0.05
 
-	air.assert_gas("o2") //only need to assert oxygen, as this reaction doesn't occur without the other gases existing
+	ASSERT_GAS("o2", air) //only need to assert oxygen, as this reaction doesn't occur without the other gases existing
 	cached_gases["o2"][MOLES] += reaction_rate
 
 	air.temperature -= (reaction_rate*20000)/air.heat_capacity()
@@ -126,7 +126,7 @@
 		if(burned_fuel)
 			energy_released += FIRE_CARBON_ENERGY_RELEASED * burned_fuel
 
-			air.assert_gas("co2")
+			ASSERT_GAS("co2", air)
 			cached_gases["co2"][MOLES] += burned_fuel
 
 			cached_results[id] += burned_fuel
@@ -142,14 +142,14 @@
 		else
 			temperature_scale = (temperature-PLASMA_MINIMUM_BURN_TEMPERATURE)/(PLASMA_UPPER_TEMPERATURE-PLASMA_MINIMUM_BURN_TEMPERATURE)
 		if(temperature_scale > 0)
-			air.assert_gas("o2")
+			ASSERT_GAS("o2", air)
 			oxygen_burn_rate = OXYGEN_BURN_RATE_BASE - temperature_scale
 			if(cached_gases["o2"][MOLES] > cached_gases["plasma"][MOLES]*PLASMA_OXYGEN_FULLBURN)
 				plasma_burn_rate = (cached_gases["plasma"][MOLES]*temperature_scale)/PLASMA_BURN_RATE_DELTA
 			else
 				plasma_burn_rate = (temperature_scale*(cached_gases["o2"][MOLES]/PLASMA_OXYGEN_FULLBURN))/PLASMA_BURN_RATE_DELTA
 			if(plasma_burn_rate > MINIMUM_HEAT_CAPACITY)
-				air.assert_gas("co2")
+				ASSERT_GAS("co2", air)
 				cached_gases["plasma"][MOLES] = QUANTIZE(cached_gases["plasma"][MOLES] - plasma_burn_rate)
 				cached_gases["o2"][MOLES] = QUANTIZE(cached_gases["o2"][MOLES] - (plasma_burn_rate * oxygen_burn_rate))
 				cached_gases["co2"][MOLES] += plasma_burn_rate
diff --git a/code/modules/atmospherics/machinery/components/trinary_devices/filter.dm b/code/modules/atmospherics/machinery/components/trinary_devices/filter.dm
index 2b5a94ef64..4e3ef0f3cc 100644
--- a/code/modules/atmospherics/machinery/components/trinary_devices/filter.dm
+++ b/code/modules/atmospherics/machinery/components/trinary_devices/filter.dm
@@ -96,7 +96,7 @@
 			var/datum/gas_mixture/filtered_out = new
 
 			filtered_out.temperature = removed.temperature
-			filtered_out.assert_gas(filter_type)
+			ASSERT_GAS(filter_type, filtered_out)
 			filtered_out.gases[filter_type][MOLES] = removed.gases[filter_type][MOLES]
 
 			removed.gases[filter_type][MOLES] = 0
@@ -166,4 +166,3 @@
 	if(. && on && is_operational())
 		to_chat(user, "<span class='warning'>You cannot unwrench [src], turn it off first!</span>")
 		return FALSE
-
diff --git a/code/modules/atmospherics/machinery/components/unary_devices/oxygen_generator.dm b/code/modules/atmospherics/machinery/components/unary_devices/oxygen_generator.dm
index e31d1efa96..0be10fecf0 100644
--- a/code/modules/atmospherics/machinery/components/unary_devices/oxygen_generator.dm
+++ b/code/modules/atmospherics/machinery/components/unary_devices/oxygen_generator.dm
@@ -47,7 +47,7 @@
 		var/added_oxygen = oxygen_content - total_moles
 
 		air_contents.temperature = (current_heat_capacity*air_contents.temperature + 20*added_oxygen*T0C)/(current_heat_capacity+20*added_oxygen)
-		air_contents.assert_gas("o2")
+		ASSERT_GAS("o2", air_contents)
 		air_contents.gases["o2"][MOLES] += added_oxygen
 
 		update_parents()
diff --git a/code/modules/atmospherics/machinery/components/unary_devices/tank.dm b/code/modules/atmospherics/machinery/components/unary_devices/tank.dm
index 4b2b1843fe..3b0055edab 100644
--- a/code/modules/atmospherics/machinery/components/unary_devices/tank.dm
+++ b/code/modules/atmospherics/machinery/components/unary_devices/tank.dm
@@ -16,7 +16,7 @@
 	air_contents.volume = volume
 	air_contents.temperature = T20C
 	if(gas_type)
-		air_contents.assert_gas(gas_type)
+		ASSERT_GAS(gas_type, air_contents)
 		air_contents.gases[gas_type][MOLES] = AIR_CONTENTS
 		name = "[name] ([air_contents.gases[gas_type][GAS_META][META_GAS_NAME]])"
 
diff --git a/code/modules/atmospherics/machinery/components/unary_devices/vent_scrubber.dm b/code/modules/atmospherics/machinery/components/unary_devices/vent_scrubber.dm
index d92b061cec..1abf84df10 100644
--- a/code/modules/atmospherics/machinery/components/unary_devices/vent_scrubber.dm
+++ b/code/modules/atmospherics/machinery/components/unary_devices/vent_scrubber.dm
@@ -196,37 +196,37 @@
 			filtered_out.temperature = removed.temperature
 
 			if(scrub_Toxins && removed_gases["plasma"])
-				filtered_out.add_gas("plasma")
+				ADD_GAS("plasma", filtered_out.gases)
 				filtered_gases["plasma"][MOLES] = removed_gases["plasma"][MOLES]
 				removed.gases["plasma"][MOLES] = 0
 
 			if(scrub_CO2 && removed_gases["co2"])
-				filtered_out.add_gas("co2")
+				ADD_GAS("co2", filtered_out.gases)
 				filtered_gases["co2"][MOLES] = removed_gases["co2"][MOLES]
 				removed_gases["co2"][MOLES] = 0
 
 			if(removed_gases["agent_b"])
-				filtered_out.add_gas("agent_b")
+				ADD_GAS("agent_b", filtered_out.gases)
 				filtered_gases["agent_b"][MOLES] = removed_gases["agent_b"][MOLES]
 				removed_gases["agent_b"][MOLES] = 0
 
 			if(scrub_N2O && removed_gases["n2o"])
-				filtered_out.add_gas("n2o")
+				ADD_GAS("n2o", filtered_out.gases)
 				filtered_gases["n2o"][MOLES] = removed_gases["n2o"][MOLES]
 				removed_gases["n2o"][MOLES] = 0
 
 			if(scrub_BZ && removed_gases["bz"])
-				filtered_out.add_gas("bz")
+				ADD_GAS("bz", filtered_out.gases)
 				filtered_gases["bz"][MOLES] = removed_gases["bz"][MOLES]
 				removed_gases["bz"][MOLES] = 0
 
 			if(scrub_Freon && removed_gases["freon"])
-				filtered_out.add_gas("freon")
+				ADD_GAS("freon", filtered_out.gases)
 				filtered_gases["freon"][MOLES] = removed_gases["freon"][MOLES]
 				removed_gases["freon"][MOLES] = 0
 
 			if(scrub_WaterVapor && removed_gases["water_vapor"])
-				filtered_out.add_gas("water_vapor")
+				ADD_GAS("water_vapor", filtered_out.gases)
 				filtered_gases["water_vapor"][MOLES] = removed_gases["water_vapor"][MOLES]
 				removed_gases["water_vapor"][MOLES] = 0
 
diff --git a/code/modules/atmospherics/machinery/other/miner.dm b/code/modules/atmospherics/machinery/other/miner.dm
index 20439e5c2b..1db4c5edd3 100644
--- a/code/modules/atmospherics/machinery/other/miner.dm
+++ b/code/modules/atmospherics/machinery/other/miner.dm
@@ -132,7 +132,7 @@
 	if(!isopenturf(O))
 		return FALSE
 	var/datum/gas_mixture/merger = new
-	merger.assert_gas(spawn_id)
+	ASSERT_GAS(spawn_id, merger)
 	merger.gases[spawn_id][MOLES] = (spawn_mol)
 	merger.temperature = spawn_temp
 	O.assume_air(merger)
diff --git a/code/modules/atmospherics/machinery/portable/canister.dm b/code/modules/atmospherics/machinery/portable/canister.dm
index 024330ed7e..c08ef25b61 100644
--- a/code/modules/atmospherics/machinery/portable/canister.dm
+++ b/code/modules/atmospherics/machinery/portable/canister.dm
@@ -174,7 +174,7 @@
 
 /obj/machinery/portable_atmospherics/canister/proc/create_gas()
 	if(gas_type)
-		air_contents.add_gas(gas_type)
+		ADD_GAS(gas_type, air_contents.gases)
 		if(starter_temp)
 			air_contents.temperature = starter_temp
 		air_contents.gases[gas_type][MOLES] = (maximum_pressure * filled) * air_contents.volume / (R_IDEAL_GAS_EQUATION * air_contents.temperature)
diff --git a/code/modules/atmospherics/machinery/portable/scrubber.dm b/code/modules/atmospherics/machinery/portable/scrubber.dm
index 93475a00a7..7a76405a90 100644
--- a/code/modules/atmospherics/machinery/portable/scrubber.dm
+++ b/code/modules/atmospherics/machinery/portable/scrubber.dm
@@ -45,7 +45,7 @@
 
 	filtered.temperature = filtering.temperature
 	for(var/gas in filtering.gases & scrubbing)
-		filtered.add_gas(gas)
+		ADD_GAS(gas, filtered.gases)
 		filtered.gases[gas][MOLES] = filtering.gases[gas][MOLES] // Shuffle the "bad" gasses to the filtered mixture.
 		filtering.gases[gas][MOLES] = 0
 	filtering.garbage_collect() // Now that the gasses are set to 0, clean up the mixture.