21 U.S.C. § 346 — Tolerances for poisonous or deleterious substances in food; regulations

Any poisonous or harmful substance added to food is automatically "unsafe" under section 342(a)(2)(A) of this title. This is true unless the substance is required to make the food, or cannot be avoided using good manufacturing practices. If the substance is required or unavoidable, the Secretary must set rules limiting how much of it can be in the food. The Secretary sets this limit at whatever level is needed to protect public health. Any amount above that limit is also treated as "unsafe" under section 342(a)(2)(A). While such a limit is in effect, food is not automatically considered "adulterated" under section 342(a)(1) for containing an allowed amount of the substance. When deciding how much of the substance to allow, the Secretary must consider two things. First, how much of the substance is truly needed or unavoidable in making each specific food. Second, how the same or other poisonous or harmful substances might otherwise affect consumers.

The record shows that this section originated as § 406 of the Federal Food, Drug, and Cosmetic Act, enacted June 25, 1938 (ch. 675, 52 Stat. 1049). The source credit indicates two subsequent amendments: one by Public Law 85–929, § 3(c), approved September 6, 1958, and another by Public Law 86–618, title I, § 103(a)(1), approved July 12, 1960. Beyond identifying these enactments and their dates, the source credit does not elaborate on the substance or purpose of each change. The 1938 Act is generally understood to have been Congress's response to perceived inadequacies in the earlier Pure Food and Drug Act of 1906, prompted in part by public alarm over unsafe pharmaceutical and food products in the preceding years. The Act's broadly cited purpose was to strengthen federal authority to regulate the safety of foods, drugs, and cosmetics, including establishing standards for identifying adulterated or misbranded food. As to why Congress specifically included a tolerance mechanism for poisonous or deleterious substances that are unavoidable in food production, the record does not establish the particular legislative reasoning. It is consistent with the Act's general aim of balancing practical manufacturing realities against public health protection, but the source credit provides no committee reports, statements of purpose, or other documentation specific to this section, and none should be presumed.