(also diethanolamine, triethanolamine and monoethanolamine) A synthetic family of surfactants, this group of compounds is used to neutralize acids in products to make them non-irritating. Diethanolamine is slow to biodegrade and reacts with natural nitrogen oxides and sodium nitrite pollutants in the atmosphere to form diethanolnitrosamine, a suspected carcinogen. Found in: Conventional personal care products and some detergents.