This subject is related to the Black Mesa Incident era.

Sector D

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Sector D
General information

200-, during the Black Mesa Incident


Black Mesa Research Facility


Black Mesa Incident


Black Mesa

Game information


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John Guthrie[a]
Marc Laidlaw[1]

"Hey, what the hell are you doing down here? Get topside! I hear troops are coming in to save us!"
Black Mesa security guard[src]

Sector D,[2] referred to as Sector D Administration,[3] is one of the seven main Sectors of the Black Mesa Research Facility.[3] It is connected to the Yellow Line of the Black Mesa Transit System.[3]

Administration Center[edit]

See also: Office Complex

The Administration Center[4] is a location featured in Half-Life in the chapter Office Complex. It is a large underground complex where the bureaucratic aspects of Black Mesa's upkeep take place along with some limited research. The floors are mostly covered with black and white tiles placed in a checkerboard fashion, typical of the area. As suggested by the name of several texture files used in the area, many parts of Sector D, notably the Administration Center, were built in the 1950s during the Cold War era.[5]


There are additional images in this gallery. Click to expand.

High Security Materials Storage Area[edit]

The High Security Materials Storage Area[4] is a location featured in Half-Life in the chapter "We've Got Hostiles". It is a large Cold War era[5] storage facility set above the Administration Center. As the military have just invaded the facility, many Sentry Guns and Laser Trip Mines have been installed, targeting civilians and alien creatures. Most areas are separated with heavy fire doors that will close when their emergency button is pressed.


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Silo D[edit]

See also: Blast Pit

Silo D is a location featured in Half-Life in the chapter Blast Pit. It is a large abandoned Cold War era missile silo that houses the Experimental Propulsion Laboratory[4] used for testing rocket engines. It is connected to the High Security Materials Storage Area by an old decommissioned rail system. It houses three silos.

Silo D-01, Engine Testing (green-coded) is located in the middle of the silo. It is the largest and most important of the three. This is where the engines are actually tested. Three huge Tentacle creatures occupy the silo. The other two silos are adjoined to this silo and can be only accessed through here.

Silo D-02, Power Facility (green-coded) provides energy to Silo D-01 and is accessed through the lowest door of the central chamber. Silo D-03, Wind Tunnel (yellow-coded) contains a huge propeller and is accessed from the upper door inside Silo D-01. The nearby Fuel Room contains the fuel and oxygen reserves provided for the Silo D-01 engines.


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Behind the scenes[edit]

According to unused textures, the train hub in Sector E was originally part of Sector D.

List of appearances[edit]

Main games[edit]



  1. The demo (.dem) files (previously recorded footage of the game) in Half-Life Alpha appears to be recorded by the creators of the maps. c1a2a.dem was recorded by Choryoth, which is the alias of John Guthrie.


  1. Game Design: Secrets of the Sages by Marc Saltzman (1999)
  2. Half-Life
  3. 3.0 3.1 3.2 Black Mesa Transit System map
  4. 4.0 4.1 4.2 Half-Life, sentences.txt
  5. 5.0 5.1 Half-Life Prima Guide
Preceded by
The Portal Device
Half-Life Alpha progression Succeeded by
The Security Complex
Preceded by
Sector B
Half-Life story arc journey Succeeded by
Sector E Materials Transport