An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Inert Reassessment Document for Tannin - CAS No. 1401-55-4

Tannin is approved for use as a dispersing agent in pesticide formulations applied to growing crops only under 40 CPR 180.920. Tannins also occur naturally in coffee and tea and nearly all wood and vegetation contain some form of tannin in the leaves, twigs, bark, wood, or fruit, including a variety of plants utilized for food and feed (food grains, fruits, wines, teas, and forages).

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.