diff --git a/code/modules/mob/living/carbon/human/life.dm b/code/modules/mob/living/carbon/human/life.dm
index 41a3125c183..4af096131fc 100644
--- a/code/modules/mob/living/carbon/human/life.dm
+++ b/code/modules/mob/living/carbon/human/life.dm
@@ -550,7 +550,7 @@
 					breath.nitrogen += inhaled_gas_used
 				if("phoron")
 					breath.phoron += inhaled_gas_used
-				if("CO2")
+				if("carbon_dioxide")
 					breath.carbon_dioxide += inhaled_gas_used
 
 		// Too much exhaled gas in the air