A person with a toxic inhalation has inhaled smoke or fumes, which damage the lungs or poison the body. Direct damage to the lungs by an inhaled chemical is called chemical pneumonia.

A toxic inhalation may directly cause damage to the lining of the air passageways. Other toxic inhalations, such as carbon monoxide poisoning, cause damage after the toxic material is absorbed by the lung and enters the bloodstream. Carbon monoxide interferes with the body's ability to use oxygen, after it enters the bloodstream and enters the tissues.