16 CFR 260.9 - Free-of claims.
(a) It is deceptive to misrepresent, directly or by implication, that a product, package, or service is free of, or does not contain or use, a substance. Such claims should be clearly and prominently qualified to the extent necessary to avoid deception.
(b) A truthful claim that a product, package, or service is free of, or does not contain or use, a substance may nevertheless be deceptive if:
(1) The product, package, or service contains or uses substances that pose the same or similar environmental risks as the substance that is not present; or
(2) The substance has not been associated with the product category.
(c) Depending on the context, a free-of or does-not-contain claim is appropriate even for a product, package, or service that contains or uses a trace amount of a substance if:
(1) The level of the specified substance is no more than that which would be found as an acknowledged trace contaminant or background level 47 ;
47 “Trace contaminant” and “background level” are imprecise terms, although allowable manufacturing “trace contaminants” may be defined according to the product area concerned. What constitutes a trace amount or background level depends on the substance at issue, and requires a case-by-case analysis.
(2) The substance's presence does not cause material harm that consumers typically associate with that substance; and
(3) The substance has not been added intentionally to the product.