diff --git a/code/game/machinery/alarm.dm b/code/game/machinery/alarm.dm
index ea06ad87299..75565e8a747 100644
--- a/code/game/machinery/alarm.dm
+++ b/code/game/machinery/alarm.dm
@@ -131,7 +131,7 @@
 			return
 
 		var/turf/simulated/location = loc
-		ASSERT(istype(location))
+		if(!istype(location))	return//returns if loc is not simulated
 
 		var/datum/gas_mixture/environment = location.return_air()
 		var/partial_pressure = R_IDEAL_GAS_EQUATION*environment.temperature/environment.volume