The applicant must provide a discussion of the impurities that may be present in the product, and why they may be present. The discussion should be based on established chemical theory and on what the applicant knows about the starting materials, technical grade of active ingredient, inert ingredients, and production or formulation process. If the applicant has reason to believe that an impurity that EPA would consider toxicologically significant may be present, the discussion must include an expanded discussion of the possible formation of the impurity and the amounts at which it might be present. The impurities which must also be discussed are the following, as applicable:
(a) Technical grade active ingredients and products produced by an integrated system.
(1) Each impurity associated with the active ingredient which was found to be present in any analysis of the product conducted by or for the applicant.
(2) Each other impurity which the registrant or applicant has reason to believe may be present in his product at any time before use at a level ≥0.1 percent (1,000 ppm) by weight of the technical grade of the active ingredient, based on what he knows about the following:
(i) The composition (or composition range) of each starting material used to produce his product.
(ii) The impurities which the applicant knows are present (or believes are likely to be present) in the starting materials, and the known or presumed level (or range of levels) of these impurities.
(iii) The intended reactions and side reactions which may occur in the production of the product, and the relative amounts of byproduct impurities produced by such reactions.
(iv) The possible degradation of the ingredients in the product after its production but prior to its use.
(v) Post-production reactions between the ingredients in the product.
(vi) The possible migration of components of packaging materials into the pesticide.
(vii) The possible carryover of contaminants from use of production equipment previously used to produce other products or substances.
(viii) The process control, purification and quality control measures used to produce the product.
(b) Products not produced by an integrated system. Each impurity associated with the active ingredient which the applicant has reason to believe may be present in the product at any time before use at a level ≥0.1 percent (1,000 ppm) by weight of the product based on what he knows about the following:
(1) The possible carryover of impurities present in any registered product which serves as the source of any of the product's active ingredients. The identity and level of impurities in the registered source need not be discussed or quantified unless known to the formulator.
(2) The possible carryover of impurities present in the inert ingredients in the product.
(3) Possible reactions occurring during the formulation of the product between any of its active ingredients, between the active ingredients and inert ingredients, or between the active ingredient and the production equipment.
(4) Post-production reactions between any of the product's active ingredients and any other component of the product or its packaging.
(5) Possible migration of packaging materials into the product.
(6) Possible contaminants resulting from earlier use of equipment to produce other products.
(c) Expanded discussion. On a case-by-case basis, the Agency may require an expanded discussion of information on impurities:
(1) From other possible chemical reactions.
(2) Involving other ingredients.
(3) At additional points in the production or formulation process.