Getting started

Is this for you at all

Updated October 2026

On this page8

What this covers The first warning, and its escape Which costs you something real The second warning, and its absence of an escape That is the rule with teeth And then the container, which has one job Two of the eight are not dry at all References

One warning is escaped by writing something on the label. The other is escaped only by doing the work.

What this covers

Bath bombs, shower steamers, bath salts, soaks, milk baths, bath teas, bath oils and bubble bath. Eight leaves, and the taxonomy treats them all as small dry parts in a wide-mouth jar, which is right for six of them.

The first warning, and its escape

A foaming detergent bath product carries a prescribed caution about irritation to skin and urinary tract, and adequate directions for safe use, except for products labeled as intended for use exclusively by adults. The exemption is a sentence on the label.

Which costs you something real

Labeling a bubble bath for adults only takes it out of the caution requirement and takes it out of the children’s market at the same time. That is a commercial decision with a regulatory shape rather than a compliance trick.

The second warning, and its absence of an escape

Each ingredient and each finished cosmetic product shall be adequately substantiated for safety prior to marketing. An unsubstantiated product is misbranded unless it bears "Warning - The safety of this product has not been determined" conspicuously on the principal display panel.

That is the rule with teeth

Not a prohibition, a required sentence that no maker would ever put on the front of a package. The regulation makes the warning the alternative to the substantiation, which is a more effective design than a ban.

And then the container, which has one job

A bath bomb works because citric acid and bicarbonate react on contact with moisture. The jar is keeping water away from a product designed to respond to it, and nothing else about the jar matters as much.

Two of the eight are not dry at all

Bath oil and bubble bath are liquids and want bottles rather than wide-mouth jars. The archetype says dispensed by scoop, which does not describe either, and the containers section says where they should go instead.

References

21 CFR 740.17, Foaming detergent bath products, which defines such a product as anything intended to be added to a bath to produce foam that contains a surface-active agent serving as a detergent or foaming ingredient, and requires a prescribed caution and adequate directions for safe use except for products labeled as intended for use exclusively by adults. law.cornell.edu

21 CFR 740.10, which requires each ingredient and each finished cosmetic product to be adequately substantiated for safety prior to marketing, and makes an unsubstantiated ingredient or product misbranded unless it bears the conspicuous statement "Warning - The safety of this product has not been determined" on the principal display panel. law.cornell.edu

21 CFR 740.1, which requires the label of a cosmetic product to bear a warning statement whenever necessary or appropriate to prevent a health hazard that may be associated with the product. law.cornell.edu

Written from federal regulation, not from a formulation bench. Substantiating the safety of a cosmetic is a real body of work and nothing here is a substitute for it. Whether a particular product is a foaming detergent bath product within 21 CFR 740.17 turns on what it is and what it is intended for.