The label
On this page9
The two options
The manufacturer discloses on the label under one of two paragraphs: a list of intentionally added ingredients that appear on a designated list, or a list of all intentionally added ingredients, the second of which permits generic terms such as "fragrances" or "colorants".
The requirement that is not optional
The label carries "the manufacturer’s toll-free telephone number and Internet Web site address". That applies whichever disclosure option is taken, and it is the clause most often missed by a maker who has carefully built an ingredient list.
A toll-free number is a real obligation
Not a mobile, not a contact form. For a one-person operation that means buying a number and answering it, and it should be set up before the label is printed rather than after somebody calls.
And the website address has to resolve
Where the label does not carry a complete ingredient list, it carries the address of a site that provides the required information. A printed address pointing at a page that does not exist yet is a compliance failure built into fifty thousand labels.
Choosing between the two options
The full-list option is more work to produce and less work to maintain, because it does not require tracking which of your ingredients appear on a designated list as those lists change. For a small range that is usually the better trade.
Panel area, again
A complete ingredient list at a legible size is a lot of label. On a 120 mL sprayer that competes directly with the product name, and it is the reason to lay out the list before choosing the bottle.
This is separate from hazard labeling
Disclosure tells a buyer what is in the product. Hazard labeling under 16 CFR 1500.121 tells them what it can do to them, with its own placement and type size rules. A product can owe both and they are satisfied by different blocks of text.
Reported date
Secondary sources consistently give 1 January 2021 for label disclosure. That date is not quoted here from the statute text, so confirm it before relying on it.