Carbonite poisoning

Carbonite poisoning was a side-effect of improper Carbon-freezing process. While Carbon sickness as an expected side-effect of being suspended in Carbonite for a long time, imperfections during thr process could poison the encased individual, who without medical assistance would eventually succumb to death. The Outlander contracted carbonite poisoning after being frozen in carbonite by the orders of Emperor Arcann, and survived only because Valkorion used the Force to save their life.

Behind the scenes
Carbonite poisoning appears in Star Wars: The Old Republic: Knights of the Fallen Empire expansion, released with Update 4.0.