DEA and TEA are often used in cosmetics and shampoos as emulsifiers and/or foaming agents. They can cause allergic reactions, eye irritation and dryness of hair and skin. DEA and TEA are "amines" (ammonia compounds) and can form cancer-causing nitrosamines when they come in contact with nitrates. They are toxic if absorbed into the body over a long period of time. (See Scientific Literature).