Glutaraldehyde is a chemical used extensively for the cold sterilization of medical, surgical, and dental equipment. It is used in health care facilities primarily for sterilizing endoscopy instruments, as well as respiratory therapy, ultrasound, and dialysis equipment. Glutaraldehyde is also used as a biocide in building cooling towers and air-conditioning units, as a tissue fixative in histochemistry and electron microscopy, and as a constituent of embalming fluids and X-ray developers. To be effective as a cold sterilant, glutaraldehyde must be activated by buffering it to an alkaline solution prior to use, typically at a concentration of 2%. Some of the sterilant products that contain glutaraldehyde include Cidex, Metricide, Wavicide, Procide, Omnicide, Sonacide, Aldesen, and Hospex. Glutaraldehyde is a strong irritant to the skin, eyes, and respiratory system. Contact with solution can cause skin sensitization, leading to allergic contact dermatitis. Vapor inhalation has been strongly implicated as a possible cause of occupational asthma. Glutaraldehyde can also aggravate pre-existing asthma and inflammatory or fibrotic lung disease.