Copy / paste from the above document.
EPA (2000) concluded that “this plant growth regulator poses no known risks to humans or the
293 environment,” and “in animals, indole-3-butyric acid is rapidly broken down to a closely related, harmless
294 chemical that occurs naturally in living organisms.”
295 IBA occurs naturally in plants and is produced by soil bacteria, as given in Questions #2 and #3. The usage
296 of IBA is limited in amount and in location, as given in Question #5. “IBA is metabolized into IAA in the
297 human body and IAA is a common metabolite in tryptophan metabolism in human,” EPA (1992). 40 CFR
298 180.1158, given above in the “Status” section, exempts the residues of IBA (and IAA) in or on food
299 commodities from the requirement of a tolerance.
300 IBA is “not listed”, “not available”, “no NTP studies”, and “no” in the categories of “Acute Toxicity”,
301 “Cancer Information”, “Endocrine Disruption”, “Reproductive and Developmental Toxicity” and
302 “Chemicals of Special Concern” in the PAN Pesticides Database (PAN, 2011).
303 EPA, in 1992, waived all toxicity data requirements for the pesticide registration of IBA because the general
304 exposure and the dietary exposure to the products containing IBA were expected to be very low (EPA,
305 1992). EPA, based on recently available data, provided that IBA, the active ingredient in the registered
306 products, is a Toxicity Category III or IV substance, in terms of “acute oral toxicity”, “acute dermal
307 toxicity”, “acute inhalation toxicity” and “acute dermal irritation” (EPA, 2010). Two LD50 values are listed
308 here as examples for evaluating IBA’s toxicity: acute oral LD50 > 2,000 mg kg-1 (rat); and acute dermal LD50
309 > 2,000 mg kg-1 (rabbit).
310 IBA might be a Toxicity Category II material in terms of corneal involvement and/or irritation cleaning in
311 8-21 days (EPA, 2010).
312 The data requirements for other items are still waived: “90-day oral”, “90-day dermal”, “90-day inhalation”
313 and “prenatal developmental” (EPA, 2010; 40 CFR 180.1158).