The National List of Allowed and Prohibited Substances identifies substances that may and may not be used in organic crop and livestock production. It also lists the substances that may be used in or on processed organic products. In general, synthetic substances are prohibited unless specifically allowed and non-synthetic substances are allowed unless specifically prohibited. For example, a vaccine used to prevent pinkeye in livestock is an allowed synthetic substance and arsenic is an example of a prohibited natural substance. Some substances on the National List may only be used in specific situations, e.g. only for certain crops or up to a maximum amount. View National List.

Adding, Removing, or Changing a Listed Substance. Any individual or organization may submit a petition to amend the National List. The National Organic Standards Board, a Federal Advisory Committee, reviews all petitions and makes formal recommendations to USDA. These recommendations serve as the basis for rulemaking actions. Learn more.

Substance Review. The National Organic Standards Board must also review all substances every five years and recommend renewing, removing, or changing each listing. This process is commonly referred to as “Sunset” review. The USDA may decide not to add a recommended substance to the National List, but the USDA may not add a substance to the List without the NOSB’s recommendation. View National List Sunset dates (PDF) | View National List criteria.

Petitioned Substances Database. Please use the drop-down box below to view an alphabetical list of National List materials and those petitioned for inclusion. Please note that substances on this site may not be used in organic production or handling unless the substance has been added to the National List through a final rule.