Can I make cleaning soap from scratch, and who regulates it?

You can, and a laundry bar or dish soap made from fats and lye is regulated by the Consumer Product Safety Commission while it stays true soap sold only for cleaning. CPSC applies FDA's definition in 21 CFR 701.20: the bulk of the product is "an alkali salt of fatty acids," its cleaning comes from those compounds, and it is "labeled, sold, and represented only as soap" [1]. Add a skin claim or a synthetic detergent and it can become an FDA cosmetic [1]. The real hazard is the lye: Dow warns that "Eye contact of only a few seconds can cause permanent damage, even blindness" [2]. There is no recipe here, for reasons explained at the end.

Who regulates what you make

What decides it is what the product is and what you say about it, in that order. From CPSC's soap guidance [1]:

The last row surprises people: CPSC says soaps "primarily intended to be used by children 12 years of age or younger" are children's products and need "a permanent tracking label," testing for total lead by a CPSC-accepted third-party lab, and a Children's Product Certificate [1].

The dish soap trap

A bar or liquid sold "for dishes and hands" mixes the two worlds. Washing dishes is cleaning; hand washing is personal care, and a claim about the user's skin points to FDA [1]. Hand and body products are not covered here. If you want to stay with CPSC, sell the product for dishes and other wares, and keep skin language off the label and listing.

The surface germ line applies here as everywhere: "antibacterial dish soap" is a germ claim. See when a cleaner becomes a pesticide.

What the label needs

Under the FHSA

Most finished soap is not a hazardous substance, and CPSC notes that precautionary labeling for soap is uncommon and usually applies to strong degreasing soaps that could irritate eyes [1]. If your product meets the FHSA definition, its label needs, in English: a signal word ("POISON, DANGER, WARNING, CAUTION"), the principal hazards, the "Common/usual or chemical name" of each hazardous component, precautions, first aid where appropriate, handling and storage instructions where needed, "Keep out of the reach of children," and the "Name and place of business of the manufacturer, packer, distributor, or seller" [3]. The decision is on is your cleaner a hazardous substance? and the full label on what a cleaning product label must say.

State rules that reach soap

• California. The Cleaning Product Right to Know Act defines a general cleaning product as "a soap, detergent, or other chemically formulated consumer product" labeled to clean or care for fabric, dishes or surfaces [4]. A laundry bar or dish soap sold in California is a designated product, with website and label ingredient disclosure; see selling cleaning products in California.
• New York. DEC's regulation covers products "containing a surfactant as a wetting or dirt-emulsifying agent, used primarily for domestic or commercial cleaning" [5]. Soap is a surfactant, so a cleaning soap appears to fall within the 1,4-dioxane rule, though true soap carries none of DEC's ethoxylated indicator ingredients. Confirm with DEC and see New York.

Handling lye

Lye here means sodium hydroxide (caustic soda) for bars and potassium hydroxide for soft or liquid soap. Both are corrosive. The steps below come from two producers' handbooks.

Before you open the container

1. Protect your eyes first. OxyChem: "Wear suitable chemical splash goggles for eye protection during the handling of caustic soda in any form," with a face shield where splashing can occur [6]. Dow requires close-fitting chemical goggles and chemical-resistant gloves at all times [2].
2. Cover your skin. OxyChem recommends rubber or coated gloves extending well above the wrist, rubber boots with trouser legs outside them, and chemical-resistant clothing [6]. Equipment choices are on protective gear for making cleaners.
3. Choose the right vessels. OxyChem says "Aluminum, copper, zinc, lead and their alloys (e.g., brass and bronze) are NOT suitable," and "Caustic soda readily attacks these materials" [6]. That rules out aluminum pots and brass fittings.
4. Have water running before you start, and know the route to the sink or shower.

Dissolving the lye

5. Add lye to water, never water to lye. OxyChem: solid caustic should be "added slowly to the surface of a well-agitated solution of water," and "Never add the water to the caustic soda" [6]. Dow gives the same rule for caustic solutions [2].
6. Expect heat. "Considerable heat is generated when solid caustic soda is dissolved in water" [6]. Dow says to start with lukewarm water at 80 to 100°F (27 to 38°C), never hot or cold, because adding caustic too fast, in one spot, or to hot or cold liquid can cause "dangerous mists, boiling, spattering, or violent eruption" [2].
7. Stir so the solid does not settle. Unstirred flake sinks and forms a slow-dissolving layer that can overheat locally and spurt [6].

If it touches you

8. Eyes: flush immediately and keep flushing. Producers differ on how long: OxyChem says at least 15 minutes [6]; Dow says to continue for 30 minutes or until a physician advises otherwise [2]; Poison Control's general advice is at least 15 to 20 minutes [7]. This page follows Dow's 30 minutes for caustic, because it is the longest, and because Dow notes that caustic causes damage without immediate pain and, unlike acids, keeps penetrating eyes and skin [2]. Get medical help.
9. Skin: remove contaminated clothing and wash with water for at least 15 minutes (OxyChem) or 30 minutes (Dow) [2][6]. Do not try to neutralize it with vinegar or another chemical; Dow says not to [2].
10. Swallowed: do not induce vomiting [2][7]. Poison Control says to give a small amount of water or milk only if the person is awake, not having a seizure and able to swallow [7]. Call Poison Control at 1-800-222-1222, or 911 if the person is struggling.

More first aid is on cleaner in the eyes, on skin or swallowed.

Child-resistant packaging: lye yes, finished soap usually a different question

16 CFR 1700.14(a)(5) requires special packaging for household substances in dry form with 10 percent or more "free or chemically unneutralized" sodium or potassium hydroxide, and other household substances with 2 percent or more [8]. Two consequences:

• If you sell lye itself, or a soapmaking kit that contains it, the lye is far above the threshold and needs child-resistant packaging.
• A finished soap is made by reacting the hydroxide with fats. The regulation's wording turns on free or unneutralized hydroxide [8]. A bar made with excess lye, or a liquid soap paste that has not finished reacting, may still carry free hydroxide. Ask your testing lab to measure free alkali on finished batches and confirm your position with CPSC. The full list is on child-resistant closures.

Why this page has no soap recipe

A soap recipe is only safe with a lye calculation for the exact oils and lye used, and an error leaves free lye in a bar that someone will handle with bare hands. Reproducing one responsibly would mean checking a named soapmaking reference's lye calculation line by line, and that has not been done, so no recipe is given. If you make soap, work from a named soapmaking text that shows its calculation for each recipe, and test finished batches for free alkali before you sell them.

What true soap does and does not do as a cleaner (film in hard water, separation with vinegar) is on castile soap and true soap.

Turning soap into a laundry or dish product

If you plan to grate a laundry bar into a powder or sell dish blocks, the format questions (dissolving, moisture, dust and packaging) are on should I make solid cleaning products?.

References

1. U.S. Consumer Product Safety Commission, *Soap Business Guidance*, undated, read October 22, 2026. https://www.cpsc.gov/Business--Manufacturing/Business-Education/Business-Guidance/Soap-Business-Guidance
2. The Dow Chemical Company, *The Caustic Soda Solution Handbook*, Form No. 102-00011, read October 22, 2026. https://dow.com/documents/102/102-00011-01-the-caustic-soda-solution-handbook.pdf.html
3. U.S. Consumer Product Safety Commission, *FHSA Requirements* (business guidance), undated, read October 22, 2026. https://cpsc.gov/Business--Manufacturing/Business-Education/Business-Guidance/FHSA-Requirements
4. California Health and Safety Code section 108952, via California Public Law, verified October 19, 2026, read October 22, 2026. https://california.public.law/codes/health_and_safety_code_section_108952
5. New York State Department of Environmental Conservation, *1,4-Dioxane Limits for Household Cleansing, Personal Care and Cosmetic Products*, undated, read October 22, 2026. https://dec.ny.gov/environmental-protection/help-for-businesses/household-personal-cosmetic-dioxane-limits
6. Occidental Chemical Corporation (OxyChem), *Caustic Soda Handbook*, 2000. https://www.ausimm.com/globalassets/insights-and-resources/minerals-processing-toolbox/caustic_soda_handbook_oxychem.pdf
7. Poison Control (National Capital Poison Center), *First Aid for Poisonings*, undated, read October 22, 2026. https://www.poison.org/first-aid-for-poisonings
8. Legal Information Institute, Cornell Law School, *16 CFR 1700.14, Substances requiring special packaging*, read October 22, 2026. https://www.law.cornell.edu/cfr/text/16/1700.14