Important Facts about MRLs
A Maximum Residue Level (MRL) is the amount of residue legally allowed in/on harvested food or animal feed commodities after the use of a crop protection chemical according to the use directions on the product’s label. In the USA, MRLs are referred to as Tolerances. Some authorities prefer Maximum Residue Limit instead of Level.
MRLs are established by regulatory authorities as part of the registration process and are set on the basis of residue data generated from supervised residue field trials. The trials are conducted according to worst case conditions, i.e. maximal seasonal rate of application and shortest pre-harvest interval.
When discussing MRLs, we often hear the term Import Tolerance. This is simply an MRL set by a regulatory authority on the basis of foreign residue data generated in accordance with a use pattern registered in the exporting country. Import Tolerances are necessary to cover crops not grown, or for which the product is not registered, in the importing country.
MRLs are not human safety standards per se, but are trading standards set at levels evaluated to be safe for consumers. Residues detected to be within the domestic MRL are a good indication that the crop protection product was used in accordance with the directions on the label.
MRLs are used for enforcement purposes; they are the regulatory reference values against which detected amounts of residue are compared by State and national laboratories involved in monitoring foods or feeds.
Differences in Global MRLs
BASF works diligently with regulatory authorities around the world to harmonize MRLs as much as possible; however, it is frequently the case that for particular chemical-crop combinations national MRLs do differ around the world. The differences are the result of one or more factors: country use patterns and/or national regulatory requirements and policies such as MRL calculation procedures, crop groupings, residue definitions, national/regional diets, human toxicological end points and consumer risk assessments.
Due to the continual updating of MRLs around the world, exporters need to pay particular attention to the MRLs in foreign markets.
If crops are being grown for export, residues in the harvested commodities must not exceed the foreign market MRLs. Users should consult an appropriate MRL source to verify the current foreign MRL(s) before using a product, e.g. USDA-FAS International MRL database and/or national MRL databases of the target markets.
USDA-FAS (Foreign Agricultural Services) International MRL database for checking foreign MRLs against US Tolerances:
Health Canada MRL database:
EU MRL database:
Japanese MRL database:
BASF’s Principal Contact for MRL questions
Phil Brindle, PhD
Global MRLs & Import Tolerances