reagents mob temp

code/modules/mob/living/carbon/human/human_defense.dm

@@ -513,3 +513,12 @@ emp_act
 		return TRUE
 	if(check_mask && wear_mask && (wear_mask.flags_cover & MASKCOVERSMOUTH))
 		return TRUE
+
+/mob/living/carbon/human/proc/reagent_safety_check(hot = TRUE)
+	if(wear_mask)
+		to_chat(src, "<span class='danger'>Your [wear_mask.name] protects you from the [hot ? "hot" : "cold"] liquid!</span>")
+		return FALSE
+	if(head)
+		to_chat(src, "<span class='danger'>Your [head.name] protects you from the [hot ? "hot" : "cold"] liquid!</span>")
+		return FALSE
+	return TRUE

code/modules/reagents/chemistry/holder.dm

@@ -554,6 +554,35 @@ var/const/INGEST = 2
 		react_type = "OBJ"
 	else
 		return
+
+	if(react_type == "LIVING" && ishuman(A))
+		var/mob/living/carbon/human/H = A
+		if(method == TOUCH)
+			var/obj/item/organ/external/head/affecting = H.get_organ("head")
+			if(affecting)
+				if(chem_temp > H.dna.species.heat_level_1)
+					if(H.reagent_safety_check())
+						to_chat(H, "<span class='danger'>You are scalded by the hot chemicals!</span>")
+						affecting.receive_damage(0, round(log(chem_temp / 50) * 10))
+						H.emote("scream")
+						H.adjust_bodytemperature(min(max((chem_temp - T0C) - 20, 5), 500))
+				else if(chem_temp < H.dna.species.cold_level_1)
+					if(H.reagent_safety_check(FALSE))
+						to_chat(H, "<span class='danger'>You are frostbitten by the freezing cold chemicals!</span>")
+						affecting.receive_damage(0, round(log(T0C - chem_temp / 50) * 10))
+						H.emote("scream")
+						H.adjust_bodytemperature(- min(max(T0C - chem_temp - 20, 5), 500))
+
+		if(method == INGEST)
+			if(chem_temp > H.dna.species.heat_level_1)
+				to_chat(H, "<span class='danger'>You scald yourself trying to consume the boiling hot substance!</span>")
+				H.adjustFireLoss(7)
+				H.adjust_bodytemperature(min(max((chem_temp - T0C) - 20, 5), 700))
+			else if(chem_temp < H.dna.species.cold_level_1)
+				to_chat(H, "<span class='danger'>You frostburn yourself trying to consume the freezing cold substance!</span>")
+				H.adjustFireLoss(7)
+				H.adjust_bodytemperature(- min(max((T0C - chem_temp) - 20, 5), 700))
+
 	for(var/datum/reagent/R in reagent_list)
 		switch(react_type)
 			if("LIVING")

code/modules/reagents/chemistry/machinery/chem_heater.dm

@@ -94,11 +94,11 @@
 
 /obj/machinery/chem_heater/Topic(href, href_list)
 	if(..())
-		return 0
+		return FALSE
 
 	if(href_list["toggle_on"])
 		if(!beaker.reagents.total_volume)
-			return
+			return FALSE
 		on = !on
 		. = 1
 
@@ -110,7 +110,7 @@
 			var/target = input("Please input the target temperature", name) as num
 			desired_temp = Clamp(target, 0, 1000)
 		else
-			return 0
+			return FALSE
 		. = 1
 
 	if(href_list["eject_beaker"])