Copper(II)oxide is harmful and should be handled wearing a dust mask. Copper(II) oxide is an irritant. It also can cause damage to the endocrine and central nervous system. Contact to the eyes can cause irritation and damage to the corneas and potentially can cause conjunctivitis. Contact to the skin can cause irritation and discoloration. Ingesting cupric oxide can lead to central nervous system depression, liver and kidney damage, gastrointestinal damage, circulatory system failure or damage to the vascular system. Inhalation can lead to damage to the lungs and septum. Inhalation of fumes of cupric oxide can lead to a disease called metal-fume fever, which has symptoms similar to influenza. Prolonged exposure to cupric oxide can lead to dermatitis and can cause a toxic build-up of copper in people with Wilson’s disease. Handling copper(II) oxide should be done in a well-ventilated area, and care should be taken to avoid contact with the skin or eyes. After handling, one should wash thoroughly.