40 CFR 153.155 - Seed treatment products.
(a) Pesticide products intended for use in treating seeds must contain an EPA-approved dye to impart an unnatural color to the seed, unless appropriate tolerances or other clearances have been established under the Federal Food, Drug and Cosmetic Act for residues of the pesticide.
(b) The following products are exempt from the requirement of paragraph (a) of this section:
(1) Products intended and labeled for use solely by commercial seed treaters, provided that the label bears a statement requiring the user to add an EPA-approved dye with the pesticide during the seed treatment process.
(2) Products intended and labeled for use solely as at-planting or hopper box treatments.
(3) Products which are gaseous in form or are used as fumigants.
(c) EPA-approved dyes for seed treatment are listed in:
(1) Sections 180.910, 180.920, and 180.950 if an exemption from the requirement of a tolerance has been established.
(2) Section 180.2010 if EPA has determined that residues of the dye will be present, if at all, at levels that are below the threshold of regulation.
(3) Section 180.2020 if it has been determined that no tolerance or exemption from the requirement of a tolerance is needed as a result of a determination by EPA that the use is unlikely to result in residues in food/feed.