Tolerances and MRLs

Seeking harmonized MRLs where feasible

Reducing impediments to trade due to un-harmonized MRLs requires a multilateral, multinational effort by governments, regulatory agencies, crop protection companies, and grower organizations.

The Definition of MRLs

What MRLs Are:

Maximum residue levels, also known as a maximum residue limits or tolerances, are the maximum concentrations of pesticide residues that are legally allowed in or on agricultural commodities at the point of market. MRLs are typically measured in parts per million (ppm).

What MRLs Are Not:

MRLs are frequently thought to be a safety standard when they are actually a trading standard. MRLs are not a measure of toxicity or of the point where residues could make a person sick. MRLs are set at much lower levels than are toxicologically significant and monitored to help ensure growers are applying pesticides according to labels.

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The Challenge: Products Meeting US MRLs May Not Align with Foreign Market MRL Standards

Whenever a pesticide is registered for use on a food or feed crop, an MRL or tolerance (as it is known in the U.S.), or exemption from the tolerance requirement, must be established. In the U.S., the EPA establishes tolerances after a thorough scientific review. FDA and the USDA enforce tolerances.

The U.S. is not alone in establishing MRLs. As countries around the globe modernize their food supply programs, they frequently establish their own national MRLs. A pesticide may need to be used at a different rate or frequency to control pests, leading to differences in MRLs for the same chemicals. Some countries define their MRLs based on active ingredients, while other nations base theirs on the active ingredient plus any compounds from the breakdown of that ingredient. Many other additional factors make the establishment of one maximum residue level for the world very difficult.

Challenges for growers emerge when foreign MRLs differ from the MRLs in the U.S. or when a foreign market does not have an MRL established for an active ingredient approved in the U.S. In such cases, growers can apply a product according to the label, be within the U.S. MRL, and still have their crop rejected in a foreign country because of a different MRL. Unfortunately, this trend has increased over recent few years.

The Solution: Establish Synchronized MRLs across the Globe

Codex Alimentarius Commission

Governments around the world are cooperating to establish synchronized MRLs and minimize differences. This effort occurs on a bilateral basis and through multilateral international organizations, such as the World Health Organization and Food and Agricultural Organization of the United Nation's Codex Alimentarius Commission. Codex MRLs are especially helpful for countries that do not otherwise establish pesticide MRLs or that have a limited list and then defer to Codex MRLs for imports.

The Private Sector: Pesticide Registrants and Grower Groups

In addition to government efforts to harmonize MRLs, private-sector entities, including pesticide registrants like Syngenta and grower groups, also seek to coordinate MRLs around the world where feasible. Pesticide registrants comply with regulatory requirements in key export markets when new MRLs are established.

Monitoring and Enforcing MRLs

MRL monitoring and enforcement differ by country. Most systems involve the federal, state, or local/provincial government collecting samples of a variety of food products, both domestic and imported, and sending them to labs to determine pesticide residue levels. When a residue level exceeds an established MRL, the country may notify the retailer, producer, shipper, or grower and seek an explanation of the violation. A record of violations is typically retained, and additional sanctions may be applied. In other cases, commodities with residues exceeding the MRL may not be able to enter the country or region and may be returned or destroyed.

For More Information

Contact the Syngenta Customer Center at 1-866-796-4368 or your local Syngenta representative for more information about MRLs and our crop protection products. You also can visit the USDA-FAS and EPA-funded MRL database,, for MRLs around the world.

Users of this information are advised that national, regional and international regulations affecting permissible Maximum Residue Levels (MRL) frequently change. Although this information is updated periodically, the user accepts that the information on Maximum Residue Levels in it may not be completely up-to-date or error free. Additionally, commodity nomenclature and residue definitions vary between countries, and country policies regarding deferral to national, regional and international standards are not always transparent. This information is intended to be an initial reference source only, and users must verify any information obtained from it with the relevant regulatory agencies in the market of interest prior to the sale or shipment of any products. Syngenta shall not be liable for any loss or damages, including, but not limited to, direct or consequential damages, loss of profit, loss of business, loss of revenue, demands, claims, actions, proceedings, damages, payments, expenses, or other liabilities occasioned to or suffered by any person acting or refraining to act as a result of the information relating to Maximum Residue Levels contained on this website, or otherwise caused by or arising, in whole or in part, in any way from user's use of this information.