Utility Maintenance Storage is a Rare key in MW4 DMZ. It opens a maintenance room in the basement under the transformer yard next to Reactor 01 at Haneul Nuclear Reactor, grid H4. The way down is a set of sunken stairs between the transformers, right in the radiation fog. Below is where the door is, how to get there and what we found inside.
- The door is in the basement under the transformer yard next to Reactor 01 at Haneul Nuclear Reactor (H4).
- Take the sunken concrete stairs down between the transformers, go through the red entrance and follow the corridor to a brown metal door.
- The yard is in the radiation fog and was a High threat area in our run, so bring a gas mask.
- Six containers plus loose items, with Nuclear Program Files as our best valuable.
Where the Utility Maintenance Storage Door Is
The Utility Maintenance Storage is in the basement under the transformer yard next to Reactor 01, on the southwest side of the Haneul Nuclear Reactor grounds, grid H4. The basement is reached by sunken concrete stairs between the transformers. At the bottom is a red entrance with a No Entry sign, and the door itself is a brown metal door in the dark corridor behind it, with a grey fuse box on the wall next to it. The yard is inside the radiation fog and was a High threat area in our run. You can also find the door under the keys layer on our interactive MW4 DMZ map.
Click to enlarge The Utility Maintenance Storage door, brightened so you can see it. 
How to Get the Utility Maintenance Storage Key
The Utility Maintenance Storage key is field loot, so it can drop from ordinary containers on Hajin. We do not know of a fixed spawn for it. Every other key and the door it opens is in our MW4 DMZ keys guide.
The Route to the Door
- Put on a gas mask and head for the transformer yard next to Reactor 01, on the southwest side of Haneul Nuclear Reactor.
- Between the transformers, find the sunken concrete stairs and walk down to the red entrance with the No Entry sign.
- Follow the corridor past the pipes and around the corner. The brown metal door with the fuse box next to it is the Utility Maintenance Storage.
What Is Inside the Utility Maintenance Storage
Behind the door is a small office with a desk and a yellow chemical storage cabinet, and a longer storage room with rows of military lockers and metal shelves. We opened six containers, a chemical storage, four military lockers and a military bag. A few more items lay loose on the shelves. There are also MINA MS41 crates and yellow medical bags in the rooms that we did not open.
Containers
The containers decide the loot. Tap one to see what it can drop in our loot data.
Loot
-
Nuclear Program Files Rare $2,000 Military Locker -
Ballistic Flight Logs Uncommon $1,000 Loose in the room -
Infantry Invasion Plans Uncommon $1,000 Chemical Storage -
Defibrillator Rare $300 Military Locker -
Reactive Metals ×2 Uncommon $200 each Military Locker, Chemical Storage -
Sedative Inhaler Uncommon $100 Military Locker -
Trip Wire ×2 Uncommon $100 each Military Locker, Loose in the room -
Smoke Grenade Common $50 Military Locker -
Snapshot Grenade Common $50 Loose in the room -
Decoy Grenade Common Military Bag -
Armor Plate ×3 Military Locker, Military Bag -
Chemicals ×17 Chemical Storage -
Synthetics ×11 Chemical Storage
From one opening in our own run. Loot is random, so your room can roll differently, and we add every new run of this key. Values are per item, from the in-game tooltips. The loot value adds up every item with a known value and the cash, so it is a lower bound: crafting resources and items without a value are not in it.
Our best valuable was a set of Nuclear Program Files in one of the military lockers, worth $2,000. The chemical storage held Infantry Invasion Plans next to a stack of Chemicals and Synthetics, and Ballistic Flight Logs lay loose on a shelf. The rest was gear, with a Defibrillator, armor plates, a Sedative Inhaler and a handful of grenades and a trip wire.
Click to enlarge The office behind the door, brightened. 
Click to enlarge Nuclear Program Files in one of the military lockers. 
Is the Utility Maintenance Storage Key Worth It?
Not really, in our opinion. To open this door you have to go into the radiation zone of Haneul, which is never a relaxed place to be, and the room behind it is small. If you are heading into the radiation anyway, the other Rare key there is the better pick. The Reactor 02 Control Room has three Legendary Hazmat Suits on the wall, and those actually help you stay in the zone. We would skip this one.
Frequently Asked Questions
Where is the Utility Maintenance Storage in MW4 DMZ?
In the basement under the transformer yard next to Reactor 01 at Haneul Nuclear Reactor, grid H4. Sunken concrete stairs between the transformers lead down to a red entrance, and the door is a brown metal door in the dark corridor behind it, next to a fuse box.
Where do you get the Utility Maintenance Storage key?
It is field loot, so it can drop from ordinary containers on Hajin. There is no fixed spawn for it that we know of.
What is inside the Utility Maintenance Storage?
A small office and a storage room with lockers and shelves. We opened six containers, a chemical storage, four military lockers and a military bag, and found Nuclear Program Files, Infantry Invasion Plans and a Defibrillator. Ballistic Flight Logs and a few grenades lay loose on the shelves.
Do you need a gas mask for the Utility Maintenance Storage?
The transformer yard is inside the radiation fog of Haneul Nuclear Reactor, so bring a gas mask or a hazmat suit. We went in with a gas mask on. Once you are down the stairs the walk to the door is short.
