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"Welcome to the H.E.V. Mark IV protective system. For use in hazardous environment conditions"
HEV suit[src]

The HEV Suit,[1] or Hazardous EnVironment suit, often called the "Hazard Suit" for convenience, is a full-body hazardous materials suit developed at the Black Mesa Research Facility. Designed for Black Mesa scientists to protect themselves from radiation, energy discharges, blunt-force trauma during the handling of hazardous materials, and the effects of traveling to Xen as part of Survey Teams.

It is predominantly worn by Gordon Freeman during much of the Half-Life series - first as the Mark IV suit in Half-Life, then as the upgraded Mark V suit in Half-Life 2. It allows him to sustain many injuries from damage that would normally fatally wound him, such as projectiles or melee attacks.

The HEV Suit is related to both the Powered Combat Vest (PCV) used by the Hazardous Environment Combat Unit (HECU), and the armored vest and helmet used by the Black Mesa Security Force.

Mark IV[]


Gordon Freeman in the Mark IV HEV Suit.

The HEV Mark IV suit worn by Gordon Freeman in Half-Life has a built-in flashlight, Geiger counter, morphine administrator (which allows Gordon to sustain serious injuries such as bullet wounds or shrapnel), an optional Long Jump Module which allows jumps over large distances (greatly increased horizontal range; vertical distance is elevated only slightly), a radio, tracking devices, and a heads-up display (HUD) which tracks health status and weapon ammunition usage, as well as including a weapons management system.

The suit contains an on-board computer system that constantly monitors the user's health and vital signs, reacting to any changes in the user's condition with activation in the aforementioned apparatus, and a soothing female-computer voice.

Additionally, the suit has an electrically hardened armor/energy shield system that can be charged at HEV chargers throughout Black Mesa. While charged, the suit provides greater protection from injury as the charge absorbs more than two-thirds of any damage or trauma experienced by the user, with the exception of fall damage, which is absorbed directly into body-integrity, and oxygen deprivation, caused by swimming without surfacing for long periods of time. With a fully charged suit, Freeman can survive several dozen bullets of small arms fire, continuous fire or even a direct hit from a rocket-propelled grenade (with a chance of losing health).

The suit also features an optional helmet, as seen on various HEV-enclosed corpses dotted around Xen, mainly at the ruined research camp seen in Blue Shift. Although, when Freeman is spotted in Opposing Force, he enters Xen through the portal without wearing a helmet, such being the situation he would need it the most. Headcrabs will never attempt to attach directly to Freeman's head either (although, in the official Half-Life manual, Freeman never allows a headcrab to attempt to).

The HEV Suit is not exclusive to Freeman. Many can be seen worn by slain Black Mesa research members on Xen. Two additional (empty) HEV storage units are seen near the start of the game in Sector C, which are used by the main protagonists of Decay, Gina Cross and Colette Green and three empty HEV storage units can be seen near the end of Lambda Core.

The suits also come in different colors. Although many, including Gordon's and the ones belonging to the corpses seen on Xen, are orange, Gina wears a beige suit, while Colette wears a maroon suit.

Freeman puts on the suit at the beginning of Half-Life, and is allowed to keep it at the end of the game by the G-Man.

Mark V[]


The Mark V Hazard Suit stored in Kleiner's Lab prior to Gordon's use.

In Half-Life 2, despite being allowed to keep it in the previous game, Freeman starts without the suit. After a visit to Dr. Isaac Kleiner, his former colleague from Black Mesa, Freeman receives an upgraded HEV suit, the Mark V.

Dr. Kleiner, as well as other characters, occasionally refer to this suit as Gordon's "old suit," indicating that it is upgraded from his old Mark IV suit; it isn't explained how Dr. Kleiner acquired it as Gordon was placed in stasis wearing it. However, the G-Man releases Gordon wearing "civvies" (presumably the blue denim 'prison' uniform) in Half-Life 2, so it is likely that he 'arranged' it somehow.

New features include a visual zooming capability, limited enhanced running (sprint) capability, an injector to administer antidote for neurotoxins such as Poison Headcrab venom, an optional ammo and health counter on the crosshair (enabled by the player in the game's "Mouse" options), and the capability to use Combine power nodes to charge the suit. This design feature would have an unexpected effect later on in the game, when the suit appears to be infused with "Dark Energy" from a Combine weapon confiscation field, allowing the suit to store twice as much energy as normal, with maximum power at 200 power units, and will heal Gordon's health back to 100%. At this point, the suit also charges much faster and efficiently, capable of going from 0 to 200, without even depleting a single charger to half capacity (normally, a charger can only give the suit 75 power units). The Mark V also increases the user's strength considerably. While other characters are seen struggling to lift and even use the gravity gun, Gordon does so with relative ease.

Unlike the Mark IV, the Mark V uses only one auxiliary power source for the flashlight, enhanced running and oxygen supply (though, as of the events of Episode 2, the flashlight now has a separate charge meter). In addition, the Long Jump Module is no longer an available upgrade found in the environment.

Gina Cross is said to have tested a Mark V prototype under the supervision of Richard Keller before the Black Mesa Incident,[2] but it is unknown how this is related, if at all, to the Mark V suit featured in Half-Life 2.

In Half-Life: Alyx it is revealed that the Mark V by the end of Episode Two has sustained visible damage to the left-hand side of the suit with clear burn marks, left suit sleeve partially torn and a small patch of the suit missing, revealing the left side of Gordon's abdomen patched up with bandages.

Detailed analysis[]

HEV Suit room

HEV Suit room in Black Mesa's Sector C. There is stored Freeman's suit, while Cross' and Green's suits are already gone.


In Black Mesa's Lambda Complex there were stored suits used by various members of the Xen survey teams.

It should be noted that HEV energy chargers in Half-Life have the trademark (TM) symbol added after the HEV letters, which suggests that the chargers, HEV suit, or both, are produced by a non-government company. An Easter egg in Half-Life 2, however, reveals an old cover of an HEV charger lacking the trademark logo.[3] However, this could be worn off like most of the HEV lettering on the faceplate.

The HEV suit is unusual compared to conventional hazard suits like Hazmat, specifically that it was designed with combat in mind (where the environment actively fights back against trespassers) as the suit possesses the ability to track weapons in hand, along with their ammunition. The suit also possesses the ability to store multiple weapons and tools, though the method by which this is accomplished is unknown.

These combat-oriented features are explained by the visits many Black Mesa personnel made to the border world of Xen which contains many dangerous and hostile forms of life.

It is notable that the Powered Combat Vest worn by the player in Opposing Force apparently uses similar technology as it is also able to replenish its power from Black Mesa HEV chargers. It is unclear which technology was invented first, though it would be reasonable to assume that, since the PCV lacked a "mark" designation, the HEV suit was developed first and the design specifications sold to the government. Similar to this, the Aperture Science Enrichment Center had an H.E.V. charger on one of the walls in the facility, but this is more likely an Easter egg than actual lore.

The symbol on Gordon's HEV suit is the lower case Greek letter Lambda, λ. This symbol is used by scientists to denote the decay constant of radioactive elements (related to the half-life of an element). As well as appearing on Gordon's suit, the symbol replaces the letter "a" in the game title, Hλlf-Life, and is the name of the complex in the Black Mesa Research Facility where teleportation experiments are conducted. The Lambda symbol is also seen in Half-Life 2 as a marking of the human resistance, seen close to hidden supplies and on the armbands of better-equipped resistance fighters.

HEV Suit voice[]

Kathy Levin recorded the HEV Suit information and warnings. They were recorded only once for Half-Life and reused in the subsequent games featuring it.

  • In a Half-Life new game, when the player obtains the HEV suit for the first time, the HEV suit voice will say 9 statements:
    • Welcome to the H.E.V. mark IV protective system, for use in hazardous environment conditions.
    • High impact reactive armor activated
    • Atmospheric contaminant sensors activated
    • Vital sign monitoring activated
    • Automatic medical systems engaged
    • Defensive weapon selection system activated
    • Munition level monitoring activated
    • Communications interface online
    • Have a very safe day!
  • When the player obtains a battery, the HEV suit will say:
    • Power # percent. (# standing for the suit power after picking up the battery, rounded down to the nearest multiple of five.)
      • When the player gets 100% power, the HEV suit says the above line with a higher, "happier" sounding voice, and it says "Power level is one hundred percent" instead of shorter "Power one hundred percent."
      • Refilling the suit's power through the use of wall chargers will not elicit any responses.
  • When the player has dropped from a fairly high place, and the health loss resulting from the fall reaches 26 or above, the HEV suit voice will say:
    • Major fracture detected
    • Automatic medical system engaged
    • Morphine administered
  • When the player also has dropped from a low place, and the health loss resulting from the fall reaches less than 10, at the next round, the HEV suit voice will also say:
    • Minor fracture detected
  • When the player receives damage from a Snark, Zombie or Xen creature attack, the HEV suit voice will say:
    • Minor lacerations detected
  • When the player receives damage from a Barnacle or large Xen creature attack, the HEV suit voice will say:
    • Major lacerations detected
  • When the player health reaches 25 or below:
    • Vital signs critical
    • Seek medical attention
  • When the player health reaches 9 or below:
    • Emergency! User death imminent
    • Seek medical attention
  • When the player's gun runs out of ammo:
    • Ammunition depleted
  • When the player obtains a Long-Jump Module, the HEV suit voice will say:
    • Power-assisted movement activated
  • When the player is exposed to radiation, the HEV suit will say:
    • Warning! Hazardous radiation levels detected!
  • (Cut)If the player is damaged by heat, the HEV suit will say:
    • Warning! Extreme heat damage detected!
  • (Cut)If the player is damaged by an electrical shock, the HEV suit will say:
    • Warning! Electrical damage detected!
  • If the player is exposed to chemical waste, the HEV suit will briefly say:
    • Warning! Hazardous chemical detected!
  • If the player is exposed to biohazards, the HEV suit will say:
    • Warning! Blood-toxin levels detected!
  • (Cut) If the player is exposed to nerve gas, the HEV suit will also say:
    • Warning! Bio-hazard detected!
  • When the player gets deep by underwater, and then exposed to oxygen levels or health reaches 75 or below, the HEV suit will also briefly say:
    • Vital signs are dropping
  • If the player is damaged by the Gargantua stomp attack, or the Houndeye sonic attack, the HEV suit will say:
    • Internal bleeding detected!
  • If the player is shot by any enemies with guns (i.e., HECU, Black Ops Assassins, Combine Metro Police and Combine soldiers), the HEV suit will say:
    • Blood loss detected!
  • If the player is poisoned by a Poison Headcrab.
    • Warning! Blood-toxin levels detected!
    • Antidote administered!

Behind the scenes[]

  • Many sounds were recorded for the HEV suit but were never used, mostly of a medical nature; for instance, "local tourniquet applied" and "adrenaline administered". These sounds are included in the files but were presumably cut due to the lack of an actual purpose within the game, since the HEV suit is mostly aesthetic. Some unused files seemed to have been for either weapon pickup or weapon selection, as there are files named as "get_shotgun.wav".
  • Originally, in Half-Life, the suit power indicator was a battery-like symbol instead of the current number next to a human figure and a vertical bar. The battery sprite remained in Half-Life: Day One.


  • In the original Half-Life, the HEV Suit's armor not only absorbed 66% of all damage received, it also reduced the total amount of damage any given attack would inflict on the player (i.e. enemy melee attacks would do a total of 6 damage instead of 10 if the suit had power). This changes in Half-Life 2, where the player receives the same amount of damage whether or not the HEV suit has any armor energy. To compensate, the HEV suit armor is more effective in Half-Life 2, absorbing 80% of all damage received instead of 66%.
  • In the texture of the HEV Suit's back in Half-Life, the word Valve can be faintly seen. This applies only to player models that use HEV Suits, not to the HEV Suit's worldmodel.
  • The Biosuit in Team Fortress Classic and Deathmatch Classic uses the Half-Life HEV model.
  • In Opposing Force, if the player manages to load Half-Life maps with console commands, the HEV Suit is replaced with a PCV.
  • By using the cheat "impulse 101" in Portal the HEV suit can be equipped along with Half Life 2's weapons. In Portal 2 it can be equipped using the command "ent_create item_suit", it lacks a model, HUD and voice lines.
  • Originally, in the first versions of Half-Life, adrenaline was supposed to be administered instead of morphine, but this was likely changed because morphine is a stronger painkiller than adrenaline and would make more sense lore wise.
  • In Half-Life: Uplink, the HEV suit was originally red instead of it's distinctive orange color, this model was reused for Colette Green's suit.
  • Most of the HEV's voice lines were cut, with its current ones being only a small fraction of what was recorded. Valve had plans to make the HEV suit more complex like it being able to add a local tourniquet to an area, tell the time (due to the cut AM and PM voice lines) and stop bleeding but likely due to the technology of the time this couldn't be done.
  • After triggering the "Morphine administered." voice line, the player is unable to trigger it again for 30 minutes.[4]





Half-Life: Opposing Force[]

Half-Life: Decay[]

Half-Life 2[]




List of appearances[]

Imagecat The Half-Life Wiki has more images related to HEV Suit.


  1. Subtitle and sentence files from any game
  2. Half-Life PlayStation 2 instruction manual
  3. File:HL2 old hev charger.jpg
  4. https://www.youtube.com/watch?v=6oPGjA5-4AM&t=280s
  5. Portal 2: Lab Rat