diff --git a/code/__DEFINES/atmospherics.dm b/code/__DEFINES/atmospherics.dm
index 2870e31eff97..175d2fcdd9e5 100644
--- a/code/__DEFINES/atmospherics.dm
+++ b/code/__DEFINES/atmospherics.dm
@@ -386,3 +386,5 @@ GLOBAL_LIST_INIT(pipe_paint_colors, sortList(list(
 	"yellow" = rgb(255,198,0)
 )))
 
+#define IMMUNE_ATMOS_REQS list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+#define NORMAL_ATMOS_REQS list("min_oxy" = 5, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 1, "min_co2" = 0, "max_co2" = 5, "min_n2" = 0, "max_n2" = 0)
diff --git a/code/modules/antagonists/borer/borer.dm b/code/modules/antagonists/borer/borer.dm
index 71877dd61f8b..4a3f73da57c5 100644
--- a/code/modules/antagonists/borer/borer.dm
+++ b/code/modules/antagonists/borer/borer.dm
@@ -79,7 +79,7 @@ GLOBAL_VAR_INIT(total_borer_hosts_needed, 3)
 	mob_size = MOB_SIZE_SMALL
 	faction = list("creature")
 	ventcrawler = VENTCRAWLER_ALWAYS
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1500
 
diff --git a/code/modules/antagonists/morph/morph.dm b/code/modules/antagonists/morph/morph.dm
index 19b0cc891523..9f9d4140cc68 100644
--- a/code/modules/antagonists/morph/morph.dm
+++ b/code/modules/antagonists/morph/morph.dm
@@ -16,7 +16,7 @@
 	status_flags = CANPUSH
 	pass_flags = PASSTABLE
 	ventcrawler = VENTCRAWLER_ALWAYS
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxHealth = 150
 	health = 150
diff --git a/code/modules/antagonists/revenant/revenant.dm b/code/modules/antagonists/revenant/revenant.dm
index 81f8facd465a..d348531bfabe 100644
--- a/code/modules/antagonists/revenant/revenant.dm
+++ b/code/modules/antagonists/revenant/revenant.dm
@@ -36,7 +36,7 @@
 	response_harm_simple = "punch through"
 	unsuitable_atmos_damage = 0
 	damage_coeff = list(BRUTE = 1, BURN = 1, TOX = 0, CLONE = 0, STAMINA = 0, OXY = 0) //I don't know how you'd apply those, but revenants no-sell them anyway.
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = INFINITY
 	harm_intent_damage = 0
diff --git a/code/modules/antagonists/slaughter/slaughter.dm b/code/modules/antagonists/slaughter/slaughter.dm
index 595fbb27f61a..56e5d76fb654 100644
--- a/code/modules/antagonists/slaughter/slaughter.dm
+++ b/code/modules/antagonists/slaughter/slaughter.dm
@@ -23,7 +23,7 @@
 	attack_sound = 'sound/magic/demon_attack1.ogg'
 	var/feast_sound = 'sound/magic/demon_consume.ogg'
 	deathsound = 'sound/magic/demon_dies.ogg'
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = INFINITY
 	faction = list("slaughter")
diff --git a/code/modules/cargo/gondolapod.dm b/code/modules/cargo/gondolapod.dm
index 560fc46668de..2a05796e67fc 100644
--- a/code/modules/cargo/gondolapod.dm
+++ b/code/modules/cargo/gondolapod.dm
@@ -20,7 +20,7 @@
 	layer = TABLE_LAYER//so that deliveries dont appear underneath it
 	loot = list(/obj/effect/decal/cleanable/blood/gibs, /obj/item/stack/sheet/animalhide/gondola = 2, /obj/item/reagent_containers/food/snacks/meat/slab/gondola = 2)
 	//Gondolas aren't affected by cold.
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1500
 	maxHealth = 200
diff --git a/code/modules/holiday/easter.dm b/code/modules/holiday/easter.dm
index a5cf4d78499e..34325454bd79 100644
--- a/code/modules/holiday/easter.dm
+++ b/code/modules/holiday/easter.dm
@@ -55,7 +55,7 @@
 	icon_state = "s_rabbit_white"
 	icon_living = "s_rabbit_white"
 	icon_dead = "s_rabbit_white_dead"
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1500
 	unsuitable_atmos_damage = 0
diff --git a/code/modules/mining/minebot.dm b/code/modules/mining/minebot.dm
index cc2a9f176c70..89f4e7eac2ce 100644
--- a/code/modules/mining/minebot.dm
+++ b/code/modules/mining/minebot.dm
@@ -13,7 +13,7 @@
 	mouse_opacity = MOUSE_OPACITY_ICON
 	faction = list("neutral")
 	a_intent = INTENT_HARM
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	move_to_delay = 10
 	health = 125
diff --git a/code/modules/mob/living/carbon/alien/special/facehugger.dm b/code/modules/mob/living/carbon/alien/special/facehugger.dm
index c9cdcaf8199c..5820f3ec4304 100644
--- a/code/modules/mob/living/carbon/alien/special/facehugger.dm
+++ b/code/modules/mob/living/carbon/alien/special/facehugger.dm
@@ -27,7 +27,7 @@
 	attack_verb_simple = "flail at"
 	attack_sound = 'sound/weapons/bladeslice.ogg'
 	faction = list(ROLE_ALIEN)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	verb_say = "squeaks"
 	verb_ask = "squeaks"
 	verb_exclaim = "shrieks"
diff --git a/code/modules/mob/living/simple_animal/bot/bot.dm b/code/modules/mob/living/simple_animal/bot/bot.dm
index 1c25a67c1dbe..8cdc5f3c6818 100644
--- a/code/modules/mob/living/simple_animal/bot/bot.dm
+++ b/code/modules/mob/living/simple_animal/bot/bot.dm
@@ -8,7 +8,7 @@
 	wander = 0
 	healable = 0
 	damage_coeff = list(BRUTE = 1, BURN = 1, TOX = 0, CLONE = 0, STAMINA = 0, OXY = 0)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	maxbodytemp = INFINITY
 	minbodytemp = 0
 	has_unlimited_silicon_privilege = 1
diff --git a/code/modules/mob/living/simple_animal/friendly/gondola.dm b/code/modules/mob/living/simple_animal/friendly/gondola.dm
index 54e8dad7edb4..0bb662979ee1 100644
--- a/code/modules/mob/living/simple_animal/friendly/gondola.dm
+++ b/code/modules/mob/living/simple_animal/friendly/gondola.dm
@@ -22,7 +22,7 @@
 	icon_living = "gondola"
 	loot = list(/obj/effect/decal/cleanable/blood/gibs, /obj/item/stack/sheet/animalhide/gondola = 1, /obj/item/reagent_containers/food/snacks/meat/slab/gondola = 1)
 	//Gondolas aren't affected by cold.
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1500
 	maxHealth = 200
diff --git a/code/modules/mob/living/simple_animal/guardian/guardian.dm b/code/modules/mob/living/simple_animal/guardian/guardian.dm
index 538a015c163b..731801e82d99 100644
--- a/code/modules/mob/living/simple_animal/guardian/guardian.dm
+++ b/code/modules/mob/living/simple_animal/guardian/guardian.dm
@@ -27,7 +27,7 @@ GLOBAL_LIST_EMPTY(parasites) //all currently existing/living guardians
 	stop_automated_movement = 1
 	movement_type = FLYING // Immunity to chasms and landmines, etc.
 	attack_sound = 'sound/weapons/punch1.ogg'
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = INFINITY
 	attack_verb_continuous = "punches"
diff --git a/code/modules/mob/living/simple_animal/hostile/abandoned_minebot.dm b/code/modules/mob/living/simple_animal/hostile/abandoned_minebot.dm
index 78432c92a4d5..58e48850c2b8 100644
--- a/code/modules/mob/living/simple_animal/hostile/abandoned_minebot.dm
+++ b/code/modules/mob/living/simple_animal/hostile/abandoned_minebot.dm
@@ -9,7 +9,7 @@
 	status_flags = CANSTUN|CANKNOCKDOWN|CANPUSH
 	mouse_opacity = MOUSE_OPACITY_ICON
 	a_intent = INTENT_HARM
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	move_to_delay = 10
 	health = 70
diff --git a/code/modules/mob/living/simple_animal/hostile/alien.dm b/code/modules/mob/living/simple_animal/hostile/alien.dm
index ec7c76f5ca61..4e42c519a225 100644
--- a/code/modules/mob/living/simple_animal/hostile/alien.dm
+++ b/code/modules/mob/living/simple_animal/hostile/alien.dm
@@ -22,7 +22,7 @@
 	bubble_icon = "alien"
 	a_intent = INTENT_HARM
 	attack_sound = 'sound/weapons/bladeslice.ogg'
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	unsuitable_atmos_damage = 15
 	faction = list(ROLE_ALIEN)
 	status_flags = CANPUSH
diff --git a/code/modules/mob/living/simple_animal/hostile/bear.dm b/code/modules/mob/living/simple_animal/hostile/bear.dm
index b6f5c58b424e..f71615fa4e50 100644
--- a/code/modules/mob/living/simple_animal/hostile/bear.dm
+++ b/code/modules/mob/living/simple_animal/hostile/bear.dm
@@ -34,7 +34,7 @@
 	friendly_verb_simple = "bear hug"
 
 	//Space bears aren't affected by cold.
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1500
 
diff --git a/code/modules/mob/living/simple_animal/hostile/bees.dm b/code/modules/mob/living/simple_animal/hostile/bees.dm
index 676b58a98520..24f6a03b7643 100644
--- a/code/modules/mob/living/simple_animal/hostile/bees.dm
+++ b/code/modules/mob/living/simple_animal/hostile/bees.dm
@@ -51,7 +51,7 @@
 	search_objects = 1 //have to find those plant trays!
 
 	//Spaceborn beings don't get hurt by space
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	del_on_death = 1
 
diff --git a/code/modules/mob/living/simple_animal/hostile/carp.dm b/code/modules/mob/living/simple_animal/hostile/carp.dm
index 67a80713d8ec..05f6d212dbb9 100644
--- a/code/modules/mob/living/simple_animal/hostile/carp.dm
+++ b/code/modules/mob/living/simple_animal/hostile/carp.dm
@@ -37,7 +37,7 @@
 	speak_emote = list("gnashes")
 
 	//Space carp aren't affected by cold.
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1500
 	faction = list("carp", "mining")
diff --git a/code/modules/mob/living/simple_animal/hostile/clown.dm b/code/modules/mob/living/simple_animal/hostile/clown.dm
index b513c74e9d58..7e3bf331f145 100644
--- a/code/modules/mob/living/simple_animal/hostile/clown.dm
+++ b/code/modules/mob/living/simple_animal/hostile/clown.dm
@@ -29,7 +29,7 @@
 	del_on_death = 1
 	loot = list(/obj/effect/mob_spawn/human/clown/corpse)
 
-	atmos_requirements = list("min_oxy" = 5, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 1, "min_co2" = 0, "max_co2" = 5, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = NORMAL_ATMOS_REQS
 	minbodytemp = 270
 	maxbodytemp = 370
 	unsuitable_atmos_damage = 10
diff --git a/code/modules/mob/living/simple_animal/hostile/cockroach.dm b/code/modules/mob/living/simple_animal/hostile/cockroach.dm
index c822268a7fe2..d8c63212e73b 100644
--- a/code/modules/mob/living/simple_animal/hostile/cockroach.dm
+++ b/code/modules/mob/living/simple_animal/hostile/cockroach.dm
@@ -7,7 +7,7 @@
 	maxHealth = 1
 	turns_per_move = 5
 	loot = list(/obj/effect/decal/cleanable/insectguts)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 270
 	maxbodytemp = INFINITY
 	pass_flags = PASSTABLE | PASSGRILLE | PASSMOB
diff --git a/code/modules/mob/living/simple_animal/hostile/eyeballs.dm b/code/modules/mob/living/simple_animal/hostile/eyeballs.dm
index 57a33c2ee02a..8c80682038ef 100644
--- a/code/modules/mob/living/simple_animal/hostile/eyeballs.dm
+++ b/code/modules/mob/living/simple_animal/hostile/eyeballs.dm
@@ -26,7 +26,7 @@
 	attack_verb_simple = "blink at"
 	attack_sound = 'sound/weapons/pierce.ogg'
 	movement_type = FLYING
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1500
 	gold_core_spawnable = HOSTILE_SPAWN
diff --git a/code/modules/mob/living/simple_animal/hostile/faithless.dm b/code/modules/mob/living/simple_animal/hostile/faithless.dm
index c9c2e131cc09..2a3eb9db4873 100644
--- a/code/modules/mob/living/simple_animal/hostile/faithless.dm
+++ b/code/modules/mob/living/simple_animal/hostile/faithless.dm
@@ -27,7 +27,7 @@
 	attack_sound = 'sound/hallucinations/growl1.ogg'
 	speak_emote = list("growls")
 
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 
 	faction = list("faithless")
diff --git a/code/modules/mob/living/simple_animal/hostile/giant_spider.dm b/code/modules/mob/living/simple_animal/hostile/giant_spider.dm
index 5e3e8d0b34d5..2f4688749312 100644
--- a/code/modules/mob/living/simple_animal/hostile/giant_spider.dm
+++ b/code/modules/mob/living/simple_animal/hostile/giant_spider.dm
@@ -220,7 +220,7 @@
 
 /mob/living/simple_animal/hostile/poison/giant_spider/ice //spiders dont usually like tempatures of 140 kelvin who knew
 	name = "giant ice spider"
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1500
 	poison_type = /datum/reagent/consumable/frostoil
@@ -229,7 +229,7 @@
 
 /mob/living/simple_animal/hostile/poison/giant_spider/nurse/ice
 	name = "giant ice spider"
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1500
 	poison_type = /datum/reagent/consumable/frostoil
@@ -237,7 +237,7 @@
 
 /mob/living/simple_animal/hostile/poison/giant_spider/hunter/ice
 	name = "giant ice spider"
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1500
 	poison_type = /datum/reagent/consumable/frostoil
diff --git a/code/modules/mob/living/simple_animal/hostile/hivebot.dm b/code/modules/mob/living/simple_animal/hostile/hivebot.dm
index 431229fefc44..4c5bcba394dc 100644
--- a/code/modules/mob/living/simple_animal/hostile/hivebot.dm
+++ b/code/modules/mob/living/simple_animal/hostile/hivebot.dm
@@ -23,7 +23,7 @@
 	projectiletype = /obj/projectile/hivebotbullet
 	faction = list("hivebot")
 	check_friendly_fire = 1
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	possible_a_intents = list(INTENT_HELP, INTENT_GRAB, INTENT_DISARM, INTENT_HARM)
 	minbodytemp = 0
 	verb_say = "states"
diff --git a/code/modules/mob/living/simple_animal/hostile/human/cat_butcher.dm b/code/modules/mob/living/simple_animal/hostile/human/cat_butcher.dm
index 0f14f615e5b6..69beaefea929 100644
--- a/code/modules/mob/living/simple_animal/hostile/human/cat_butcher.dm
+++ b/code/modules/mob/living/simple_animal/hostile/human/cat_butcher.dm
@@ -16,7 +16,7 @@
 	attack_verb_simple = "slash at"
 	attack_sound = 'sound/weapons/circsawhit.ogg'
 	loot = list(/obj/effect/mob_spawn/human/corpse/cat_butcher, /obj/item/circular_saw, /obj/item/gun/syringe)
-	atmos_requirements = list("min_oxy" = 5, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 1, "min_co2" = 0, "max_co2" = 5, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = NORMAL_ATMOS_REQS
 	faction = list("hostile")
 	check_friendly_fire = TRUE
 	var/impatience = 0
diff --git a/code/modules/mob/living/simple_animal/hostile/human/frontiersman.dm b/code/modules/mob/living/simple_animal/hostile/human/frontiersman.dm
index d8b4af5344ea..741bd91a3018 100644
--- a/code/modules/mob/living/simple_animal/hostile/human/frontiersman.dm
+++ b/code/modules/mob/living/simple_animal/hostile/human/frontiersman.dm
@@ -10,7 +10,7 @@
 	melee_damage_upper = 15
 	loot = list(/obj/effect/mob_spawn/human/corpse/frontier,
 				/obj/item/melee/knife/survival)
-	atmos_requirements = list("min_oxy" = 5, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 1, "min_co2" = 0, "max_co2" = 5, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = NORMAL_ATMOS_REQS
 	faction = list(FACTION_ANTAG_FRONTIERSMEN)
 	footstep_type = FOOTSTEP_MOB_SHOE
 
@@ -20,7 +20,7 @@
 	loot = list(/obj/effect/mob_spawn/human/corpse/frontier,
 				/obj/item/clothing/mask/gas/sechailer,
 				/obj/item/tank/internals/emergency_oxygen/engi)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 
 
@@ -42,7 +42,7 @@
 				/obj/item/gun/ballistic/revolver/shadow,
 				/obj/item/clothing/mask/gas/sechailer,
 				/obj/item/tank/internals/emergency_oxygen/engi)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 
 /mob/living/simple_animal/hostile/human/frontier/ranged/internals/neutered
@@ -68,7 +68,7 @@
 				/obj/item/gun/ballistic/rifle/illestren,
 				/obj/item/clothing/mask/gas/sechailer,
 				/obj/item/tank/internals/emergency_oxygen/engi)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 
 /mob/living/simple_animal/hostile/human/frontier/ranged/mosin/internals/neutered
@@ -96,7 +96,7 @@
 				/obj/item/gun/ballistic/shotgun/brimstone,
 				/obj/item/clothing/mask/gas,
 				/obj/item/tank/internals/emergency_oxygen/engi)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 
 /mob/living/simple_animal/hostile/human/frontier/ranged/trooper/internals/neutered
@@ -124,7 +124,7 @@
 				/obj/item/gun/ballistic/automatic/assault/skm,
 				/obj/item/clothing/mask/gas,
 				/obj/item/tank/internals/emergency_oxygen/engi)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 
 /mob/living/simple_animal/hostile/human/frontier/ranged/trooper/internals/neutered
@@ -151,7 +151,7 @@
 				/obj/item/gun/ballistic/rifle/illestren,
 				/obj/item/clothing/mask/gas,
 				/obj/item/tank/internals/emergency_oxygen/engi)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 
 /mob/living/simple_animal/hostile/human/frontier/ranged/trooper/rifle/internals/neutered
@@ -180,7 +180,7 @@
 	loot = list(/obj/effect/mob_spawn/human/corpse/frontier/ranged/trooper/heavy,
 				/obj/item/clothing/mask/gas,
 				/obj/item/tank/internals/emergency_oxygen/engi)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 
 
@@ -211,7 +211,7 @@
 				/obj/item/gun/ballistic/automatic/pistol/mauler,
 				/obj/item/clothing/mask/gas,
 				/obj/item/tank/internals/emergency_oxygen/engi)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 
 /mob/living/simple_animal/hostile/human/frontier/ranged/officer/internals/neutered
diff --git a/code/modules/mob/living/simple_animal/hostile/human/human.dm b/code/modules/mob/living/simple_animal/hostile/human/human.dm
index 633bd40090e8..c9e68be5b005 100644
--- a/code/modules/mob/living/simple_animal/hostile/human/human.dm
+++ b/code/modules/mob/living/simple_animal/hostile/human/human.dm
@@ -30,7 +30,7 @@
 	loot = list(/obj/effect/mob_spawn/human/corpse/damaged)
 	del_on_death = TRUE
 
-	atmos_requirements = list("min_oxy" = 5, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 1, "min_co2" = 0, "max_co2" = 5, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = NORMAL_ATMOS_REQS
 	unsuitable_atmos_damage = 15
 	minbodytemp = 180
 	status_flags = CANPUSH
diff --git a/code/modules/mob/living/simple_animal/hostile/human/nanotrasen.dm b/code/modules/mob/living/simple_animal/hostile/human/nanotrasen.dm
index 6c1676d202ab..4af97a761e70 100644
--- a/code/modules/mob/living/simple_animal/hostile/human/nanotrasen.dm
+++ b/code/modules/mob/living/simple_animal/hostile/human/nanotrasen.dm
@@ -7,7 +7,7 @@
 	stat_attack = HARD_CRIT
 	melee_damage_upper = 15
 	loot = list(/obj/effect/mob_spawn/human/corpse/nanotrasensoldier)
-	atmos_requirements = list("min_oxy" = 5, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 1, "min_co2" = 0, "max_co2" = 5, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = NORMAL_ATMOS_REQS
 	faction = list(ROLE_DEATHSQUAD)
 	check_friendly_fire = TRUE
 	dodging = TRUE
@@ -72,7 +72,7 @@
 	rapid_melee = 3
 	retreat_distance = 0
 	minimum_distance = 1
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	projectiletype = /obj/projectile/beam/laser
 	projectilesound = 'sound/weapons/laser.ogg'
diff --git a/code/modules/mob/living/simple_animal/hostile/human/pirate.dm b/code/modules/mob/living/simple_animal/hostile/human/pirate.dm
index df10cfa6a2b4..c206e9e7bd87 100644
--- a/code/modules/mob/living/simple_animal/hostile/human/pirate.dm
+++ b/code/modules/mob/living/simple_animal/hostile/human/pirate.dm
@@ -5,7 +5,7 @@
 	icon_living = "piratemelee"
 	icon_dead = "pirate_dead"
 	speak_chance = 0
-	atmos_requirements = list("min_oxy" = 5, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 1, "min_co2" = 0, "max_co2" = 5, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = NORMAL_ATMOS_REQS
 	speak_emote = list("yarrs")
 	loot = list(/obj/effect/mob_spawn/human/corpse/pirate,
 			/obj/item/melee/transforming/energy/sword/saber/pirate)
@@ -31,7 +31,7 @@
 	icon_state = "piratespace"
 	icon_living = "piratespace"
 	icon_dead = "piratespace_dead"
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	speed = 1
 
@@ -71,7 +71,7 @@
 	icon_state = "piratespaceranged"
 	icon_living = "piratespaceranged"
 	icon_dead = "piratespaceranged_dead"
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	speed = 1
 
diff --git a/code/modules/mob/living/simple_animal/hostile/human/skeleton.dm b/code/modules/mob/living/simple_animal/hostile/human/skeleton.dm
index 12a3c2b2604c..4eac3878efa1 100644
--- a/code/modules/mob/living/simple_animal/hostile/human/skeleton.dm
+++ b/code/modules/mob/living/simple_animal/hostile/human/skeleton.dm
@@ -19,7 +19,7 @@
 	attack_verb_continuous = "slashes"
 	attack_verb_simple = "slash"
 	attack_sound = 'sound/hallucinations/growl1.ogg'
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	unsuitable_atmos_damage = 10
 	stat_attack = HARD_CRIT
 	faction = list("skeleton")
diff --git a/code/modules/mob/living/simple_animal/hostile/human/syndicate.dm b/code/modules/mob/living/simple_animal/hostile/human/syndicate.dm
index a88a79610b60..fd5118134f47 100644
--- a/code/modules/mob/living/simple_animal/hostile/human/syndicate.dm
+++ b/code/modules/mob/living/simple_animal/hostile/human/syndicate.dm
@@ -13,7 +13,7 @@
 	speak_chance = 0
 	stat_attack = HARD_CRIT
 	loot = list(/obj/effect/mob_spawn/human/corpse/syndicatesoldier)
-	atmos_requirements = list("min_oxy" = 5, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 1, "min_co2" = 0, "max_co2" = 5, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = NORMAL_ATMOS_REQS
 	maxbodytemp = 400
 	unsuitable_atmos_damage = 15
 	faction = list(FACTION_ANTAG_SYNDICATE)
@@ -29,7 +29,7 @@
 	name = "Ramzi Clique Commando"
 	maxHealth = 170
 	health = 170
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1000
 	speed = 1
@@ -64,7 +64,7 @@
 	name = "Ramzi Clique Commando"
 	maxHealth = 170
 	health = 170
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1000
 	speed = 1
@@ -117,7 +117,7 @@
 	name = "Ramzi Clique Commando"
 	maxHealth = 170
 	health = 170
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1000
 	speed = 1
@@ -165,7 +165,7 @@
 	name = "Ramzi Clique Commando"
 	maxHealth = 170
 	health = 170
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1000
 	speed = 1
@@ -195,7 +195,7 @@
 	name = "Ramzi Clique Commando"
 	maxHealth = 170
 	health = 170
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1000
 	speed = 1
@@ -226,7 +226,7 @@
 	name = "Ramzi Clique Commando"
 	maxHealth = 170
 	health = 170
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1000
 	speed = 1
@@ -275,7 +275,7 @@
 	attack_verb_simple = "cut"
 	attack_sound = 'sound/weapons/bladeslice.ogg'
 	faction = list(ROLE_SYNDICATE)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1000
 	mob_size = MOB_SIZE_TINY
diff --git a/code/modules/mob/living/simple_animal/hostile/human/zombie.dm b/code/modules/mob/living/simple_animal/hostile/human/zombie.dm
index 7a12465b98bb..e13461a49568 100644
--- a/code/modules/mob/living/simple_animal/hostile/human/zombie.dm
+++ b/code/modules/mob/living/simple_animal/hostile/human/zombie.dm
@@ -16,7 +16,7 @@
 	attack_verb_simple = "bite"
 	attack_sound = 'sound/hallucinations/growl1.ogg'
 	a_intent = INTENT_HARM
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	status_flags = CANPUSH
 	loot = list()
diff --git a/code/modules/mob/living/simple_animal/hostile/jungle/_jungle_mobs.dm b/code/modules/mob/living/simple_animal/hostile/jungle/_jungle_mobs.dm
index 32dc8d4bc887..4a0970751d9b 100644
--- a/code/modules/mob/living/simple_animal/hostile/jungle/_jungle_mobs.dm
+++ b/code/modules/mob/living/simple_animal/hostile/jungle/_jungle_mobs.dm
@@ -1,6 +1,6 @@
 /mob/living/simple_animal/hostile/jungle
 	vision_range = 5
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	faction = list("jungle")
 	weather_immunities = list("acid")
 	obj_damage = 30
diff --git a/code/modules/mob/living/simple_animal/hostile/megafauna/cult_templar.dm b/code/modules/mob/living/simple_animal/hostile/megafauna/cult_templar.dm
index c06c78068ce9..bf5809265172 100644
--- a/code/modules/mob/living/simple_animal/hostile/megafauna/cult_templar.dm
+++ b/code/modules/mob/living/simple_animal/hostile/megafauna/cult_templar.dm
@@ -448,7 +448,7 @@
 	stop_automated_movement = 1
 	status_flags = CANPUSH
 	attack_sound = 'sound/magic/demon_attack1.ogg'
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	faction = list("cult")
 	maxHealth = 60
 	health = 60
diff --git a/code/modules/mob/living/simple_animal/hostile/megafauna/megafauna.dm b/code/modules/mob/living/simple_animal/hostile/megafauna/megafauna.dm
index 37934c0367e5..120bf4825999 100644
--- a/code/modules/mob/living/simple_animal/hostile/megafauna/megafauna.dm
+++ b/code/modules/mob/living/simple_animal/hostile/megafauna/megafauna.dm
@@ -15,7 +15,7 @@
 	robust_searching = TRUE
 	ranged_ignores_vision = TRUE
 	stat_attack = DEAD
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	damage_coeff = list(BRUTE = 1, BURN = 0.5, TOX = 1, CLONE = 1, STAMINA = 0, OXY = 1)
 	minbodytemp = 0
 	maxbodytemp = INFINITY
diff --git a/code/modules/mob/living/simple_animal/hostile/mimic.dm b/code/modules/mob/living/simple_animal/hostile/mimic.dm
index 0568533c1e0c..68e026aa876d 100644
--- a/code/modules/mob/living/simple_animal/hostile/mimic.dm
+++ b/code/modules/mob/living/simple_animal/hostile/mimic.dm
@@ -23,7 +23,7 @@
 	speak_emote = list("creaks")
 	taunt_chance = 30
 
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 
 	faction = list("mimic")
diff --git a/code/modules/mob/living/simple_animal/hostile/mining_mobs/hivelord.dm b/code/modules/mob/living/simple_animal/hostile/mining_mobs/hivelord.dm
index bd9133ffce20..2bae8ea2a5dc 100644
--- a/code/modules/mob/living/simple_animal/hostile/mining_mobs/hivelord.dm
+++ b/code/modules/mob/living/simple_animal/hostile/mining_mobs/hivelord.dm
@@ -365,7 +365,7 @@
 	del_on_death = TRUE
 	sentience_type = SENTIENCE_BOSS
 	loot = list(/obj/item/organ/regenerative_core/legion = 3, /obj/effect/mob_spawn/human/corpse/damaged/legioninfested = 5, /obj/effect/mob_spawn/human/corpse/damaged/legioninfested = 5, /obj/effect/mob_spawn/human/corpse/damaged/legioninfested = 5)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = INFINITY
 	move_to_delay = 7
diff --git a/code/modules/mob/living/simple_animal/hostile/mining_mobs/mining_mobs.dm b/code/modules/mob/living/simple_animal/hostile/mining_mobs/mining_mobs.dm
index 6beb2f23b9e6..b5781a200e61 100644
--- a/code/modules/mob/living/simple_animal/hostile/mining_mobs/mining_mobs.dm
+++ b/code/modules/mob/living/simple_animal/hostile/mining_mobs/mining_mobs.dm
@@ -1,7 +1,7 @@
 //the base mining mob
 /mob/living/simple_animal/hostile/asteroid
 	vision_range = 2
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	faction = list("mining")
 	weather_immunities = list("lava","ash")
 	obj_damage = 30
diff --git a/code/modules/mob/living/simple_animal/hostile/netherworld.dm b/code/modules/mob/living/simple_animal/hostile/netherworld.dm
index 25827781b4b8..cdfd783155ee 100644
--- a/code/modules/mob/living/simple_animal/hostile/netherworld.dm
+++ b/code/modules/mob/living/simple_animal/hostile/netherworld.dm
@@ -15,7 +15,7 @@
 	faction = list("nether")
 	speak_emote = list("screams")
 	gold_core_spawnable = HOSTILE_SPAWN
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	lighting_alpha = LIGHTING_PLANE_ALPHA_MOSTLY_INVISIBLE
 	var/phaser = TRUE
diff --git a/code/modules/mob/living/simple_animal/hostile/retaliate/bat.dm b/code/modules/mob/living/simple_animal/hostile/retaliate/bat.dm
index 4f671f37ac68..2a3c67f1d188 100644
--- a/code/modules/mob/living/simple_animal/hostile/retaliate/bat.dm
+++ b/code/modules/mob/living/simple_animal/hostile/retaliate/bat.dm
@@ -36,7 +36,7 @@
 
 
 	//Space bats need no air to fly in.
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 
 /mob/living/simple_animal/hostile/retaliate/bat/Initialize()
diff --git a/code/modules/mob/living/simple_animal/hostile/retaliate/clown.dm b/code/modules/mob/living/simple_animal/hostile/retaliate/clown.dm
index 75610b382cb3..8f0ddee0286a 100644
--- a/code/modules/mob/living/simple_animal/hostile/retaliate/clown.dm
+++ b/code/modules/mob/living/simple_animal/hostile/retaliate/clown.dm
@@ -29,7 +29,7 @@
 	del_on_death = 1
 	loot = list(/obj/effect/mob_spawn/human/clown/corpse)
 
-	atmos_requirements = list("min_oxy" = 5, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 1, "min_co2" = 0, "max_co2" = 5, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = NORMAL_ATMOS_REQS
 	minbodytemp = 270
 	maxbodytemp = 370
 	unsuitable_atmos_damage = 10
diff --git a/code/modules/mob/living/simple_animal/hostile/retaliate/ghost.dm b/code/modules/mob/living/simple_animal/hostile/retaliate/ghost.dm
index 8b9d0d666bfb..992505fd5eb5 100644
--- a/code/modules/mob/living/simple_animal/hostile/retaliate/ghost.dm
+++ b/code/modules/mob/living/simple_animal/hostile/retaliate/ghost.dm
@@ -25,7 +25,7 @@
 	speak_emote = list("weeps")
 	deathmessage = "wails, disintegrating into a pile of ectoplasm!"
 	loot = list(/obj/item/ectoplasm)
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1500
 	movement_type = FLYING
diff --git a/code/modules/mob/living/simple_animal/hostile/retaliate/spaceman.dm b/code/modules/mob/living/simple_animal/hostile/retaliate/spaceman.dm
index 80e5968cbc4d..3338ce3a0ef9 100644
--- a/code/modules/mob/living/simple_animal/hostile/retaliate/spaceman.dm
+++ b/code/modules/mob/living/simple_animal/hostile/retaliate/spaceman.dm
@@ -51,7 +51,7 @@
 	faction = list("nanotrasenprivate")
 	a_intent = INTENT_HARM
 	loot = list(/obj/effect/mob_spawn/human/corpse/nanotrasensoldier)
-	atmos_requirements = list("min_oxy" = 5, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 1, "min_co2" = 0, "max_co2" = 5, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = NORMAL_ATMOS_REQS
 	unsuitable_atmos_damage = 15
 	status_flags = CANPUSH
 	search_objects = 1
diff --git a/code/modules/mob/living/simple_animal/hostile/space_dragon.dm b/code/modules/mob/living/simple_animal/hostile/space_dragon.dm
index 3375cd0a7269..a40b9043ee67 100644
--- a/code/modules/mob/living/simple_animal/hostile/space_dragon.dm
+++ b/code/modules/mob/living/simple_animal/hostile/space_dragon.dm
@@ -44,7 +44,7 @@
 	mouse_opacity = MOUSE_OPACITY_ICON
 	butcher_results = list(/obj/item/stack/ore/diamond = 5, /obj/item/stack/sheet/sinew = 5, /obj/item/stack/sheet/bone = 30)
 	deathmessage = "screeches as its wings turn to dust and it collapses on the floor, life estinguished."
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 	maxbodytemp = 1500
 	faction = list("carp")
diff --git a/code/modules/mob/living/simple_animal/hostile/statue.dm b/code/modules/mob/living/simple_animal/hostile/statue.dm
index bac0b4b1d51b..69ddbf9d9b5b 100644
--- a/code/modules/mob/living/simple_animal/hostile/statue.dm
+++ b/code/modules/mob/living/simple_animal/hostile/statue.dm
@@ -28,7 +28,7 @@
 	attack_verb_simple = "claw"
 	attack_sound = 'sound/hallucinations/growl1.ogg'
 
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	minbodytemp = 0
 
 	faction = list("statue")
diff --git a/code/modules/mob/living/simple_animal/hostile/tree.dm b/code/modules/mob/living/simple_animal/hostile/tree.dm
index 41efc6993d9d..40af87531a90 100644
--- a/code/modules/mob/living/simple_animal/hostile/tree.dm
+++ b/code/modules/mob/living/simple_animal/hostile/tree.dm
@@ -81,7 +81,7 @@
 	loot = list(/obj/item/stack/rods)
 	speak_emote = list("polls")
 	faction = list()
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	is_tree = FALSE
 
 /mob/living/simple_animal/hostile/tree/festivus/attack_hand(mob/living/carbon/human/M)
diff --git a/code/modules/mob/living/simple_animal/hostile/venus_human_trap.dm b/code/modules/mob/living/simple_animal/hostile/venus_human_trap.dm
index 52ddcc72963a..13d8dd57ba42 100644
--- a/code/modules/mob/living/simple_animal/hostile/venus_human_trap.dm
+++ b/code/modules/mob/living/simple_animal/hostile/venus_human_trap.dm
@@ -96,7 +96,7 @@
 	a_intent = INTENT_HARM
 	ranged_cooldown_time = 45
 	attack_sound = 'sound/weapons/bladeslice.ogg'
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 	unsuitable_atmos_damage = 0
 	lighting_alpha = LIGHTING_PLANE_ALPHA_MOSTLY_INVISIBLE
 	faction = list("hostile","vines","plants")
diff --git a/code/modules/mob/living/simple_animal/simple_animal.dm b/code/modules/mob/living/simple_animal/simple_animal.dm
index 3670e14a6405..642d40548036 100644
--- a/code/modules/mob/living/simple_animal/simple_animal.dm
+++ b/code/modules/mob/living/simple_animal/simple_animal.dm
@@ -59,7 +59,7 @@
 
 	///Atmos effect - Yes, you can make creatures that require plasma or co2 to survive. N2O is a trace gas and handled separately, hence why it isn't here. It'd be hard to add it. Hard and me don't mix (Yes, yes make all the dick jokes you want with that.) - Errorage
 	///Leaving something at 0 means it's off - has no maximum.
-	var/list/atmos_requirements = list("min_oxy" = 5, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 1, "min_co2" = 0, "max_co2" = 5, "min_n2" = 0, "max_n2" = 0)
+	var/list/atmos_requirements = NORMAL_ATMOS_REQS
 	///This damage is taken when atmos doesn't fit all the requirements above.
 	var/unsuitable_atmos_damage = 2
 
diff --git a/code/modules/mob/living/simple_animal/slime/slime.dm b/code/modules/mob/living/simple_animal/slime/slime.dm
index cb4b76983563..6cdfb6b2782a 100644
--- a/code/modules/mob/living/simple_animal/slime/slime.dm
+++ b/code/modules/mob/living/simple_animal/slime/slime.dm
@@ -24,7 +24,7 @@
 	bubble_icon = "slime"
 	initial_language_holder = /datum/language_holder/slime
 
-	atmos_requirements = list("min_oxy" = 0, "max_oxy" = 0, "min_tox" = 0, "max_tox" = 0, "min_co2" = 0, "max_co2" = 0, "min_n2" = 0, "max_n2" = 0)
+	atmos_requirements = IMMUNE_ATMOS_REQS
 
 	maxHealth = 150
 	health = 150