diff --git a/assets/level/floor/floor_6x9.mesh b/assets/level/floor/floor_6x9.mesh
index 4c1520f..6009bfc 100644
Binary files a/assets/level/floor/floor_6x9.mesh and b/assets/level/floor/floor_6x9.mesh differ
diff --git a/assets/level/hallway/hallway_4.mesh b/assets/level/hallway/hallway_4.mesh
index f5d9c3a..9b4af08 100644
Binary files a/assets/level/hallway/hallway_4.mesh and b/assets/level/hallway/hallway_4.mesh differ
diff --git a/src/equipment/spray.gd b/src/equipment/spray.gd
index 1ef74ab..f31ff67 100644
--- a/src/equipment/spray.gd
+++ b/src/equipment/spray.gd
@@ -15,12 +15,18 @@ func _spray() -> void:
 
 
 func _fire() -> void:
+	rumbler.intensity = RUMBLE_INTENSITY
+
+	if Game.manager.is_tank_full():
+		Player.instance.hud.play_tank_full_alert()
+		idle()
+		return
+
 	_spray()
 
 	spray_effect.visible = true
 	beam_particles_1.emitting = true
 	beam_particles_2.emitting = true
-	rumbler.intensity = RUMBLE_INTENSITY
 
 
 func _idle() -> void:
diff --git a/src/equipment/toothbrush/toothbrush.gd b/src/equipment/toothbrush/toothbrush.gd
index 372d65f..9d58228 100644
--- a/src/equipment/toothbrush/toothbrush.gd
+++ b/src/equipment/toothbrush/toothbrush.gd
@@ -14,7 +14,7 @@ const BRUSH_SCALE := 0.2
 
 
 func _fire() -> void:
-	if raycast.is_colliding():
+	if raycast.is_colliding() and not Game.manager.is_tank_full():
 		brush_animation.play("brush")
 		var collider := raycast.get_collider()
 		if collider is GunkBody:
diff --git a/src/game/game.gd b/src/game/game.gd
index f1ceb58..d5d9630 100644
--- a/src/game/game.gd
+++ b/src/game/game.gd
@@ -5,3 +5,5 @@ class_name Game extends Node
 static var manager: GameManagerType:
 	get():
 		return GameManager
+
+static var hud: PlayerHUD
diff --git a/src/game/game_manager.gd b/src/game/game_manager.gd
index 95024c3..96d2850 100644
--- a/src/game/game_manager.gd
+++ b/src/game/game_manager.gd
@@ -15,6 +15,9 @@ signal alert_cleared
 
 const MAX_ALERT := 6
 
+## Maximum amount of grunk the player can carry in their tank.
+@export var grunk_tank_limit := 120000
+
 ## Amount of grunk the player is currently carrying.
 var grunk_tank := 0.0
 
@@ -44,6 +47,14 @@ func deposit_tank() -> void:
 	empty_tank()
 
 
+func is_tank_full() -> bool:
+	return grunk_tank >= grunk_tank_limit
+
+
+func get_tank_fill_pct() -> float:
+	return grunk_tank / grunk_tank_limit
+
+
 ## Raise the alert level, if possible.
 func raise_alert(delta: int) -> void:
 	var new_value := clampi(alert_level + delta, 0, MAX_ALERT)
diff --git a/src/player/player.gd b/src/player/player.gd
index 7be6cbf..4404092 100644
--- a/src/player/player.gd
+++ b/src/player/player.gd
@@ -16,7 +16,7 @@ var gravity: Vector3 = (
 var selected_interactive: Interactive
 var firing := false
 
-@onready var player_hud: PlayerHUD = %PlayerHUD
+@onready var hud: PlayerHUD = %PlayerHUD
 
 @onready var camera_pivot: CameraController = %CameraPivot
 
@@ -27,6 +27,13 @@ var firing := false
 @onready var wide_spray: WideSpray = %WideSpray
 @onready var toothbrush: Tool = %Toothbrush
 
+## Global static access to player singleton
+static var instance: Player
+
+
+func _ready() -> void:
+	instance = self
+
 
 func get_speed() -> float:
 	if is_on_floor():
@@ -51,7 +58,7 @@ func get_tool() -> Tool:
 func _physics_process(delta: float) -> void:
 	# Will be null if no valid interactor is selected.
 	var interactive: Interactive = interact_ray.get_collider() as Interactive
-	player_hud.select_interactive(interactive)
+	hud.select_interactive(interactive)
 
 	# World interaction
 	if interactive and Input.is_action_just_pressed("interact"):
diff --git a/src/props/overhead_light/overhead_light.tscn b/src/props/overhead_light/overhead_light.tscn
index 4ee14ec..bf7fccf 100644
--- a/src/props/overhead_light/overhead_light.tscn
+++ b/src/props/overhead_light/overhead_light.tscn
@@ -55,6 +55,33 @@ _surfaces = [{
 blend_shape_mode = 0
 shadow_mesh = SubResource("ArrayMesh_3gl0p")
 
+[sub_resource type="Animation" id="Animation_g27yp"]
+length = 0.001
+tracks/0/type = "value"
+tracks/0/imported = false
+tracks/0/enabled = true
+tracks/0/path = NodePath(".:mesh:surface_0/material:emission_energy_multiplier")
+tracks/0/interp = 1
+tracks/0/loop_wrap = true
+tracks/0/keys = {
+"times": PackedFloat32Array(0),
+"transitions": PackedFloat32Array(1),
+"update": 0,
+"values": [12.0]
+}
+tracks/1/type = "value"
+tracks/1/imported = false
+tracks/1/enabled = true
+tracks/1/path = NodePath("../SpotLight3D:light_energy")
+tracks/1/interp = 1
+tracks/1/loop_wrap = true
+tracks/1/keys = {
+"times": PackedFloat32Array(0),
+"transitions": PackedFloat32Array(1),
+"update": 0,
+"values": [2.0]
+}
+
 [sub_resource type="Animation" id="Animation_whqf3"]
 resource_name = "flicker"
 length = 0.01
@@ -85,33 +112,6 @@ tracks/1/keys = {
 "values": [3.0, 2.7]
 }
 
-[sub_resource type="Animation" id="Animation_g27yp"]
-length = 0.001
-tracks/0/type = "value"
-tracks/0/imported = false
-tracks/0/enabled = true
-tracks/0/path = NodePath(".:mesh:surface_0/material:emission_energy_multiplier")
-tracks/0/interp = 1
-tracks/0/loop_wrap = true
-tracks/0/keys = {
-"times": PackedFloat32Array(0),
-"transitions": PackedFloat32Array(1),
-"update": 0,
-"values": [12.0]
-}
-tracks/1/type = "value"
-tracks/1/imported = false
-tracks/1/enabled = true
-tracks/1/path = NodePath("../SpotLight3D:light_energy")
-tracks/1/interp = 1
-tracks/1/loop_wrap = true
-tracks/1/keys = {
-"times": PackedFloat32Array(0),
-"transitions": PackedFloat32Array(1),
-"update": 0,
-"values": [2.0]
-}
-
 [sub_resource type="AnimationLibrary" id="AnimationLibrary_ngq1d"]
 _data = {
 &"RESET": SubResource("Animation_g27yp"),
diff --git a/src/ui/hud/grunk_counter/grunk_counter.gd b/src/ui/hud/grunk_counter/grunk_counter.gd
index b3f38cf..1b31269 100644
--- a/src/ui/hud/grunk_counter/grunk_counter.gd
+++ b/src/ui/hud/grunk_counter/grunk_counter.gd
@@ -4,6 +4,8 @@ extends HBoxContainer
 const COUNTER_BUMP_RATE := 0.15
 const COUNTER_SPINDOWN_TIME := 0.4
 
+const TANK_WARNING_BUFFER_PCT := 0.1
+
 @onready var counter: Label = %Counter
 
 
@@ -14,11 +16,14 @@ func _ready() -> void:
 
 
 func on_grunk_collected(delta: float) -> void:
-	counter.text = str(int(Game.manager.grunk_tank))
+	counter.text = str(int(clampf(Game.manager.grunk_tank, 0.0, Game.manager.grunk_tank_limit)))
 	counter.scale = Vector2.ONE + Vector2.ONE * clampf(delta / 128.0, 0.1, 1.0)
+	var buffer := remap(Game.manager.get_tank_fill_pct(), 1 - TANK_WARNING_BUFFER_PCT, 1, 0, 1)
+	counter.modulate = Color.WHITE.lerp(Color.RED, clampf(buffer, 0, 1))
 
 
 func on_grunk_emptied(amount: float) -> void:
+	counter.modulate = Color.WHITE
 	create_tween().tween_method(_set_counter, int(amount), 0, COUNTER_SPINDOWN_TIME).set_trans(
 		Tween.TRANS_EXPO
 	)
diff --git a/src/ui/hud/grunk_counter/grunk_counter.tscn b/src/ui/hud/grunk_counter/grunk_counter.tscn
index 3f35997..bb189fc 100644
--- a/src/ui/hud/grunk_counter/grunk_counter.tscn
+++ b/src/ui/hud/grunk_counter/grunk_counter.tscn
@@ -23,8 +23,9 @@ text = "GRUNK: "
 [node name="Counter" type="Label" parent="."]
 unique_name_in_owner = true
 texture_filter = 6
+custom_minimum_size = Vector2(120, 0)
 layout_mode = 2
 size_flags_horizontal = 4
 size_flags_vertical = 8
-text = "       0"
+text = "0"
 horizontal_alignment = 2
diff --git a/src/ui/hud/player_hud.gd b/src/ui/hud/player_hud.gd
index e25de67..3e6448e 100644
--- a/src/ui/hud/player_hud.gd
+++ b/src/ui/hud/player_hud.gd
@@ -7,6 +7,7 @@ class_name PlayerHUD extends Control
 
 func _ready() -> void:
 	Game.manager.alert_raised.connect(_on_raise_alert)
+	Game.hud = self
 
 
 func select_interactive(prop: Interactive) -> void:
@@ -15,3 +16,7 @@ func select_interactive(prop: Interactive) -> void:
 
 func _on_raise_alert(_new_value: int) -> void:
 	alert_player.play("grunk_alert")
+
+
+func play_tank_full_alert() -> void:
+	alert_player.play("tank_full_alert")
diff --git a/src/ui/hud/player_hud.tscn b/src/ui/hud/player_hud.tscn
index 5bac013..9bc6e54 100644
--- a/src/ui/hud/player_hud.tscn
+++ b/src/ui/hud/player_hud.tscn
@@ -1,4 +1,4 @@
-[gd_scene load_steps=8 format=3 uid="uid://dq1x21tq06dud"]
+[gd_scene load_steps=9 format=3 uid="uid://dq1x21tq06dud"]
 
 [ext_resource type="Theme" uid="uid://b07fevr214mmr" path="res://src/ui/hud/hud_theme.tres" id="1_lirk3"]
 [ext_resource type="Script" uid="uid://lrsv0185bfu" path="res://src/ui/hud/player_hud.gd" id="2_j6lpx"]
@@ -31,6 +31,18 @@ tracks/1/keys = {
 "update": 0,
 "values": [Color(1, 1, 1, 0)]
 }
+tracks/2/type = "value"
+tracks/2/imported = false
+tracks/2/enabled = true
+tracks/2/path = NodePath("TankAlert:modulate")
+tracks/2/interp = 1
+tracks/2/loop_wrap = true
+tracks/2/keys = {
+"times": PackedFloat32Array(0),
+"transitions": PackedFloat32Array(1),
+"update": 0,
+"values": [Color(1, 1, 1, 0)]
+}
 
 [sub_resource type="Animation" id="Animation_5be8f"]
 resource_name = "grunk_alert"
@@ -61,10 +73,28 @@ tracks/1/keys = {
 "values": [Color(1, 1, 1, 0), Color(1, 1, 1, 0), Color(1, 1, 1, 1), Color(1, 1, 1, 0), Color(1, 1, 1, 1), Color(1, 1, 1, 0)]
 }
 
+[sub_resource type="Animation" id="Animation_ud8na"]
+resource_name = "tank_full_alert"
+length = 3.6
+step = 0.1
+tracks/0/type = "value"
+tracks/0/imported = false
+tracks/0/enabled = true
+tracks/0/path = NodePath("TankAlert:modulate")
+tracks/0/interp = 1
+tracks/0/loop_wrap = true
+tracks/0/keys = {
+"times": PackedFloat32Array(0, 0.6, 1.2, 1.8, 2.4, 3, 3.6),
+"transitions": PackedFloat32Array(1, 1, 1, 1, 1, 1, 1),
+"update": 0,
+"values": [Color(1, 1, 1, 0), Color(1, 1, 1, 1), Color(1, 1, 1, 0), Color(1, 1, 1, 1), Color(1, 1, 1, 0), Color(1, 1, 1, 1), Color(1, 1, 1, 0)]
+}
+
 [sub_resource type="AnimationLibrary" id="AnimationLibrary_ud8na"]
 _data = {
 &"RESET": SubResource("Animation_n6jee"),
-&"grunk_alert": SubResource("Animation_5be8f")
+&"grunk_alert": SubResource("Animation_5be8f"),
+&"tank_full_alert": SubResource("Animation_ud8na")
 }
 
 [node name="PlayerHUD" type="Control"]
@@ -148,6 +178,21 @@ grow_horizontal = 2
 grow_vertical = 2
 mouse_filter = 1
 
+[node name="TankAlert" type="Label" parent="AlertHUD"]
+modulate = Color(1, 1, 1, 0)
+layout_mode = 1
+anchors_preset = 5
+anchor_left = 0.5
+anchor_right = 0.5
+offset_left = -268.0
+offset_right = 268.0
+offset_bottom = 88.0
+grow_horizontal = 2
+theme_type_variation = &"AlertLabel"
+text = "TANK FULL
+RETURN TO SHIP"
+horizontal_alignment = 1
+
 [node name="GrunkAlert" type="Label" parent="AlertHUD"]
 modulate = Color(1, 1, 1, 0)
 layout_mode = 1