Updated to july 2020.

code/game/machinery/shuttle/shuttle_engine.dm

@@ -130,7 +130,7 @@
 	var/deltaTemperature = req_power / heat_cap
 	if(deltaTemperature < 0)
 		return
-	env.temperature += deltaTemperature
+	env.set_temperature(env.return_temperature(),deltaTemperature)
 	air_update_turf()
 
 /obj/machinery/shuttle/engine/default_change_direction_wrench(mob/user, obj/item/I)

code/game/machinery/shuttle/shuttle_heater.dm

@@ -89,8 +89,8 @@
 	var/datum/gas_mixture/air_contents = airs[1]
 	if(!air_contents)
 		return
-	air_contents.volume = gas_capacity
-	air_contents.temperature = T20C
+	air_contents.set_volume(gas_capacity)
+	air_contents.set_temperature(T20C)
 
 /obj/machinery/atmospherics/components/unary/shuttle/heater/proc/hasFuel(var/required)
 	var/datum/gas_mixture/air_contents = airs[1]

code/game/objects/items/pet_carrier.dm

@@ -253,7 +253,7 @@
 		occupant_gas_supply = new
 	if(isanimal(occupant))
 		var/mob/living/simple_animal/animal = occupant
-		occupant_gas_supply.temperature = animal.minbodytemp //simple animals only care about temperature when their turf isnt a location
+		occupant_gas_supply.set_temperature(animal.minbodytemp) //simple animals only care about temperature when their turf isnt a location
 	else
 		if(ishuman(occupant)) //humans require resistance to cold/heat and living in no air while inside, and lose this when outside
 			ADD_TRAIT(occupant, TRAIT_RESISTCOLD, "bluespace_container_cold_resist")

code/game/objects/items/tanks/tank_types.dm

@@ -19,7 +19,7 @@
 	dog_fashion = /datum/dog_fashion/back
 
 
-/obj/item/tank/internals/oxygen/New()
+/obj/item/tank/internals/oxygen/populate_gas()
 	air_contents.set_moles(/datum/gas/oxygen, (6*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C))
 	return
 
@@ -47,7 +47,7 @@
 	item_state = "an_tank"
 	force = 10
 
-/obj/item/tank/internals/anesthetic/New()
+/obj/item/tank/internals/anesthetic/populate_gas()
 	air_contents.set_moles(/datum/gas/oxygen, (3*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C) * O2STANDARD)
 	air_contents.set_moles(/datum/gas/nitrous_oxide, (3*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C) * N2STANDARD)
 	return
@@ -63,7 +63,7 @@
 	force = 10
 	dog_fashion = /datum/dog_fashion/back
 
-/obj/item/tank/internals/air/New()
+/obj/item/tank/internals/air/populate_gas()
 	air_contents.set_moles(/datum/gas/oxygen, (6*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C) * O2STANDARD)
 	air_contents.set_moles(/datum/gas/nitrogen, (6*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C) * N2STANDARD)
 	return
@@ -81,7 +81,7 @@
 	force = 8
 
 
-/obj/item/tank/internals/plasma/New()
+/obj/item/tank/internals/plasma/populate_gas()
 	air_contents.set_moles(/datum/gas/plasma, (3*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C))
 	return
 
@@ -98,7 +98,7 @@
 	else
 		return ..()
 
-/obj/item/tank/internals/plasma/full/New()
+/obj/item/tank/internals/plasma/full/populate_gas()
 	air_contents.set_moles(/datum/gas/plasma, (10*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C))
 
 //Makes empty oxygen tanks spawn without gas
@@ -106,7 +106,7 @@
 	return
 
 /obj/item/tank/internals/plasma/full/populate_gas()
-	air_contents.gases[/datum/gas/plasma] = (10*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C)
+	air_contents.set_moles(/datum/gas/plasma, (10*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C))
 
 /*
  * Plasmaman Plasma Tank
@@ -120,11 +120,11 @@
 	force = 10
 	distribute_pressure = TANK_DEFAULT_RELEASE_PRESSURE
 
-/obj/item/tank/internals/plasmaman/New()
+/obj/item/tank/internals/plasmaman/populate_gas()
 	air_contents.set_moles(/datum/gas/plasma, (3*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C))
 	return
 
-/obj/item/tank/internals/plasmaman/full/New()
+/obj/item/tank/internals/plasmaman/full/populate_gas()
 	air_contents.set_moles(/datum/gas/plasma, (10*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C))
 	return
 
@@ -137,7 +137,7 @@
 	volume = 6
 	w_class = WEIGHT_CLASS_SMALL //thanks i forgot this
 
-/obj/item/tank/internals/plasmaman/belt/full/New()
+/obj/item/tank/internals/plasmaman/belt/full/populate_gas()
 	air_contents.set_moles(/datum/gas/plasma, (10*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C))
 	return
 
@@ -160,7 +160,7 @@
 	volume = 3 //Tiny. Real life equivalents only have 21 breaths of oxygen in them. They're EMERGENCY tanks anyway -errorage (dangercon 2011)
 
 
-/obj/item/tank/internals/emergency_oxygen/New()
+/obj/item/tank/internals/emergency_oxygen/populate_gas()
 	air_contents.set_moles(/datum/gas/oxygen, (3*ONE_ATMOSPHERE)*volume/(R_IDEAL_GAS_EQUATION*T20C))
 	return