Acetaldehyde (A132600) is used as a marker to determine ALDH2-deficiency in humans. There is genetic-epidemiologic and biochemical evidence linking this deficiency to acetaldehyde exposure and resulting in cancer of the upper digestive tract (1). It has been used as an agent in the measurement of endogenous epinephrine and norepinephrine in human plasma (2). It is also used to label the amine groups on biogenic monoamine neurotransmitters for simultaneous panel determination (3). Drinking water contaminant candidate list 3 (CCL 3) compound as per United States Environmental Protection Agency (EPA), environmental, and food contaminants.