Formaldehyde poisoning occurs when a person is exposed to formaldehyde gas, an odorless, toxic gas that is slightly heavier than air. Harmful effects of exposure to formaldehyde gas may include: irritation of the eyes, skin, and respiratory tract, accumulation of fluid in the lungs, narrowing of the bronchi (main passage into the lungs), injury to the gastrointestinal tract, poor blood flow (circulatory shock), breathing difficulties, build up of acid in the body (metabolic acidosis), and kidney failure (acute renal failure). Examples of formaldehyde uses include: as a disinfectant, to preserve/embalm specimens, and in photography. Formaldehyde is a human carcinogen, meaning it is known to cause cancer. There is no specific medication to reverse the harmful effects, but treatment may include: decontamination, for example, by flushing eyes and skin with water, and giving the person added oxygen.