Freezer burn, as it is known throughout the UNSC, is an injury caused from cryopreservation in the cryo chambers of UNSC ships. Freezer burn is directly caused by the breakdown of cryo-sleep pharmaceuticals trapped in muscles and joints. The condition has been described as an agonizing sensation, like a "bad case of pins and needles".
During the freezing and resuscitation process, cloth or other materials, bandages for example, next to or against the skin causes cellular damage. This results in large welts or rashes on the covered areas, described as a making the skin "blistered and raw". Most UNSC personnel are stored in cryo either naked to avoid freezer burn, or clothed and willing to endure the various injuries. It is likely that such injuries are very easy to treat, especially given the level of medical technology in the 26th century.
Staff Sergeant Avery Johnson suffered from freezer burn due to long stretches of cryo-sleep during his travels between Tribute, Earth, and Harvest. Spartans can be stored in cryo-preservation fully clad in MJOLNIR armor without the effects dulling their combat performance, as they are trained to dispel pain. Since their regenerative capabilities are somewhat beyond a normal human's, it is possible that they heal even faster than a normal human would.
- In Halo: The Flood, it is stated that John-117 had freezer burn when exiting the UNSC Pillar of Autumn's cryo pod, while in Halo: Combat Evolved it is stated that he had "no signs of freezer burn".
- In Halo Wars, The Package, and Halo: Fall of Reach - Boot Camp, characters are shown undergoing cryosleep fully clothed, despite the risk of freezer burn. This is probably a liberty taken due to the developers not wanting to implement nudity. Halo 4: Forward Unto Dawn introduces skin-tight clothes designed to be worn during cryosleep, which may suggest that tight-fit clothing, (like that worn by Anders and Halsey, and even the MJOLNIR armor's undersuit), can stave off the effects of freezer burn.
List of appearances
- Halo: Combat Evolved (First mentioned)
- Halo: The Flood (Mentioned only)
- Halo: Contact Harvest (First appearance)
- Halo: Combat Evolved Anniversary (Mentioned only)