The Food and Drug Administration is proposing "to affirm" that urea, a substance found in urine, is "generally recognized as safe" (a phrase also known as GRAS) as a direct human food ingredient. The examination of urea is part of FDA's comprehensive review of human food ingredients previously classified as safe.

Urea is already listed as safe for use in cotton and cotton fabrics used for dry food packaging, in paper products and in food containers.

In addition, the FDA has written several opinion letters stating that urea is safe for use in vitamin and mineral preparations, as a dietary supplement in syrups used in flavoring milk and in chewing gum.

FDA said a literature search by its Select Committee on GRAS Substances found that urea appears to cause birth defects in chick and frog embryos, but no such effect was observed after pregnant rats and cows ingested large doses of urea.

The committee said a certain amount of urea can be ingested by man "without untoward effects." Since most urea produced is used in fertilizer, animal feed and resins, such as urea-formaldehyde resins, the committee estimated that the average amount of urea consumed by humans is well below a level that would pose any health hazard.