Abstract
An international effort is under way to harmonize the procedures and assumptions used for establishing maximum residue levels (MRL) for residues of veterinary drugs and pesticides. Apparent conflicts in MRLs may not actually reflect differing safety assessments for the residues but may be due to different safety factors, methods of analysis, consumption factors, etc. Equivalence is an important principle in the U.S. position on agricultural trade. Countries wishing to export food products to the U.S. must demonstrate that their country's residue control programs are equivalent to the U.S. program. From the U.S. export perspective, there have been several instances of trade problems resulting from different MRLs. The most significant was the decision by the European Economic Community not to accept U.S. beef if the animals were administered anabolic steroids. Another example involved the Japanese rejection of U.S. pork because of sulfamethazine residues. These examples illustrate the importance of harmonization to future efforts to facilitate free trade and reduce the resource burden on government regulatory bodies.