Liquefied hydrocarbon gas, such as propane is considered safe. However there are reports that voluntary exposure to liquefied gas at least could originate hallucinatory states. We report a 20 years old woman who was found in a coma with extensor muscle hypertonia, brisk tendon reflexes and extensor plantar (Babinski) responses after being exposed to propane gas. The brain magnetic resonance imaging (MRI) showed lesions in both hippocampi and white matter in the oval center. The patient had a normal oxygen saturation of 98%, a carboxyhemoglobin of 1.6% and a metabolic acidosis with a pH of 7.01 with an anion gap of 16 mEq/l. This pattern suggested that it was a consequence of the intermediary metabolism of isopropanol. The recovery of the patient was slow and four months later she still had lesions on MRI and limitations in her cognitive sphere, memory and executive functions. Thus, liquefied gas exposure can cause a toxic encephalopathy with a persistent damage of the central nervous system.