The safety assessment of food-packaging materials has attracted relatively little public interest in comparison with the attention paid to the safety of direct food additives. Nevertheless, a considerable and increasing proportion of regulatory effort in matters relating to chemical safety of food is devoted worldwide to assessment of the safety-in-use of food-packaging materials. This is probably for several reasons. First, the number of substances involved is very large, i.e., some several thousand, compared, for example, with only 400 or so direct food additives (if flavoring substances are excluded) or a similar number of pesticides. Second, the materials used in food packaging are constantly changing with fast-moving technological innovations, which are characteristic of this area. Third, for some substances originating from food-packaging materials, the amounts migrating into food may be similar or even greater in quantity than the amounts of direct additives present in foods. Because of transfer into food, packaging migrants are termed indirect food additives in the United States of America. Elsewhere they are usually referred to as contaminants.