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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.
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