diff --git a/code/modules/clothing/clothing.dm b/code/modules/clothing/clothing.dm
index 0a9ecad292..92f18afcc1 100644
--- a/code/modules/clothing/clothing.dm
+++ b/code/modules/clothing/clothing.dm
@@ -1,7 +1,6 @@
 /obj/item/clothing
 	name = "clothing"
 	var/list/species_restricted = null //Only these species can wear this kit.
-	var/gas_filter_strength = 0			//For gas mask filters
 
 //BS12: Species-restricted clothing check.
 /obj/item/clothing/mob_can_equip(M as mob, slot)
diff --git a/code/modules/clothing/masks/gasmask.dm b/code/modules/clothing/masks/gasmask.dm
index 44bf751967..b89b8831af 100644
--- a/code/modules/clothing/masks/gasmask.dm
+++ b/code/modules/clothing/masks/gasmask.dm
@@ -9,7 +9,7 @@
 	gas_transfer_coefficient = 0.01
 	permeability_coefficient = 0.01
 	siemens_coefficient = 0.9
-	gas_filter_strength = 1
+	var/gas_filter_strength = 1			//For gas mask filters
 
 //Plague Dr suit can be found in clothing/suits/bio.dm
 /obj/item/clothing/mask/gas/plaguedoctor
diff --git a/code/modules/mob/living/carbon/human/life.dm b/code/modules/mob/living/carbon/human/life.dm
index d514a4f95b..0164ca1227 100644
--- a/code/modules/mob/living/carbon/human/life.dm
+++ b/code/modules/mob/living/carbon/human/life.dm
@@ -334,10 +334,14 @@
 						if(head.flags & BLOCK_GAS_SMOKE_EFFECT)
 							block = 1
 
-					if(!block && !wear_mask)
-						breath = loc.remove_air(breath_moles, 0)
+					if(block && wear_mask)
+						if(istype(wear_mask, /obj/item/clothing/mask/gas))
+							var/obj/item/clothing/mask/gas/G = wear_mask
+							breath = loc.remove_air(breath_moles, G.gas_filter_strength) //Filters out harmful gases
+						else
+							breath = loc.remove_air(breath_moles, 0)
 					else
-						breath = loc.remove_air(breath_moles, wear_mask.gas_filter_strength) //Filters out harmful gases
+						breath = loc.remove_air(breath_moles, 0)
 
 					if(!is_lung_ruptured())
 						if(!breath || breath.total_moles < BREATH_MOLES / 5 || breath.total_moles > BREATH_MOLES * 5)
diff --git a/code/modules/mob/living/carbon/monkey/life.dm b/code/modules/mob/living/carbon/monkey/life.dm
index 84228208c9..be549e2c62 100644
--- a/code/modules/mob/living/carbon/monkey/life.dm
+++ b/code/modules/mob/living/carbon/monkey/life.dm
@@ -232,13 +232,16 @@
 						if(istype(wear_mask, /obj/item/clothing/mask/gas))
 							block = 1
 
-					if(!block)
-						breath = loc.remove_air(breath_moles, 0)
+					if(block && wear_mask)
+						if(istype(wear_mask, /obj/item/clothing/mask/gas))
+							var/obj/item/clothing/mask/gas/G = wear_mask
+							breath = loc.remove_air(breath_moles, G.gas_filter_strength) //Filters out harmful gases
+						else
+							breath = loc.remove_air(breath_moles, 0)
 					else
-						breath = loc.remove_air(breath_moles, wear_mask.gas_filter_strength) //Filters out harmful gases
+						breath = loc.remove_air(breath_moles, 0)
 
 					if(!block)
-
 						for(var/obj/effect/effect/chem_smoke/smoke in view(1, src))
 							if(smoke.reagents.total_volume)
 								smoke.reagents.reaction(src, INGEST)