I can't for the life of me find the publication where congress defined a tobacco product.
The one from Congress - the Family Smoking Prevention and Tobacco Control Act (FSPTCA or TCA) is here:
Frequently Asked Questions on the Passage of the Family Smoking Prevention and Tobacco Control Act (FSPTCA) Updated October, 2010
What products are considered to be tobacco products as defined by the Tobacco Control Act?
The term “tobacco product” means any product made or derived from tobacco that is intended for human consumption, including any component, part, or accessory of a tobacco product. This includes, among other products, cigarettes, cigarette tobacco, roll-your-own tobacco, and smokeless tobacco.
What products are not considered to be tobacco products as defined by the Tobacco Control Act?
The term “tobacco product” does not apply to raw materials other than tobacco used in manufacturing a component, part, or accessory of a tobacco product. Nor does it mean something that is defined as a drug, device, or combination product under the Federal Food, Drug, and Cosmetic Act.
However, the FDA deeming has 'deemed' it differently than Congress where 'made or derived from tobacco' is no longer applicable (except in the sections on labeling where some 'range' is allowed). Instead anything that is 'intended for human consumption' - the use of component parts, are now 'tobacco products'.
Some lawsuits are addressing this disparity from what Congress wrote and intended, vs. how the FDA wants to redefine in order to affect electronic cigarettes.
https://brvliquids.com/wp-content/uploads/2016/06/R2B-Complaint.pdf
Count Six pg. 32
112. Under the TCA, the term “tobacco product” is defined to mean, in part, “any
product made or derived from tobacco that is intended for human consumption, including any
component, part, or accessory of a tobacco product.” 21 U.S.C. § 321(rr).
113. In the Deeming Rule, FDA defines “component or part” as “any software or
assembly of materials intended or reasonably expected: (1) To alter or affect the tobacco
product’s performance, composition, constituents, or characteristics; or (2) To be used with or
for the human consumption of a tobacco product.” 21 U.S.C. § 1100.3. Components and parts
are subject to regulation under the Deeming Rule. 81 Fed. Reg. at 28,975.