Orange B
15139-76-1 · Acid Orange 137 · BLQVZCMYWIKAGV-UHFFFAOYSA-L · HSDB 7975 · 1-(4-Sulfophenyl)-3-ethylcarboxy-4-(4-sulfonaphthylazo)-5-hydroxypyrazole disodium · 1H-Pyrazole-3-carboxylic acid, 4,5-dihydro-5-oxo-4-((4-sulfo-1-naphthalenyl)azo)-1-(4-sulfophenyl)-, 3-ethyl ester, disodi · 1H-Pyrazole-3-carboxylic acid, 4,5-dihydro-5-oxo-4-((4-sulfo-1-naphthalenyl)azo)-1-(4-sulfophenyl)-, 3-ethyl ester, disodium salt · 1H-Pyrazole-3-carboxylicacid,4,5-dihydro-5-oxo-4-[2-(4-sulfo-1-naphthalenyl)diazenyl]-1-(4-sulfophenyl)-,3-ethyl ester, sodium salt (1:2) · 2-Pyrazoline-3-carboxylic acid, 5-oxo-4-((4-sulfo-1-naphthyl)azo)-1-(p-sulfophenyl)-, 2-ethyl ester, disodium salt · 3-Ethyl 4,5-dihydro-5-oxo-4-((4-sulfo-1-naphthalenyl)azo)-1-(4-sulfophenyl)-1H-pyrazole-3-carboxylate disodium salt · Disodium 1-(4-sulfophenyl)-3-ethylcarboxy-4-(4-sulfonaphthylazo)-5-hydroxypyrazole · Disodium 3-ethyl 4,5-dihydro-5-oxo-4-((4-sulfo-1-naphthalenyl)azo)-1-(4-sulfophenyl)-1H-pyrazole-3-carboxylate · Disodium 3-ethyl 4,5-dihydro-5-oxo-4-((4-sulphonato-1-naphthyl)azo)-1-(4-sulphonatophenyl)-1H-pyrazole-3-carboxylate · Disodium 3-ethyl 5-oxo-4-((4-sulfo-1-naphthyl)azo)-1-(p-sulfophenyl)-2-pyrazoline-3-carboxylate · disodium;4-[[3-ethoxycarbonyl-5-oxo-1-(4-sulfonatophenyl)-4H-pyrazol-4-yl]diazenyl]naphthalene-1-sulfonate · Ethyl 5-oxo-4-(4-sulfonaphthylazo)-1-(p-sulfophenyl)-2-pyrazoline-3-carboxylate disodium salt · Sodium 4-((3-(ethoxycarbonyl)-5-oxo-1-(4-sulfonatophenyl)-4,5-dihydro-1H-pyrazol-4-yl)diazenyl)naphthalene-1-sulfonate · Orange BCAS 15139-76-1
Orange B is a synthetic dye that was permitted in the United States for one purpose only: colouring the casings or surfaces of frankfurters and sausages. The FDA revoked that listing with effect from 8 September 2026, finding the use abandoned: Orange B had not been batch certified since 1978. It is not on the EU's list of authorised food additives.
Where it is and isn’t permitted
| Jurisdiction | Status | Scope and limits | Citation |
|---|---|---|---|
| Australia and New Zealand | No listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it. | ||
| Canada | No listing matchedHealth Canada’s lists name additives without E or INS numbers, so this site matches them by exact name. A substance listed there under a name this site does not recognise has no row here. | ||
| European Union | No listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it. | ||
| Great Britain | No listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it. | ||
| Japan | No listing matchedThis site imports only Japan’s list of designated additives (Appended Table 1 to the Regulations for Enforcement of the Food Sanitation Act), matched by English name. Existing additives, natural flavouring agents and ordinary foods used as additives are permitted outside that list and are not imported, so an empty row does not show that Japan does not permit the substance. | ||
| South Korea | No listing matchedThis site imports Part III of South Korea’s Standards and Specifications for Food Additives, matched by CAS number, then INS number, then exact name. Mixed preparations and sanitisers are not imported, and an entry whose identifiers disagreed with a page’s is held for review, so an empty row does not show that South Korea does not permit the substance. | ||
| United States | DelistedRemoved from this jurisdiction’s permitted list with effect from 8 September 2026. The regulatory changes below cite the instrument. | Removing instrument | |
| Codex Alimentarius | Not listedDoes not appear on this jurisdiction’s permitted list. That is not the same as being prohibited. |
Regulatory changes
Dated acts affecting this additive, then anything the weekly comparison of the imported lists has seen move. The status panel above shows where the rules stand now; these are the decisions that got them there.
· United States
Orange B no longer permitted as a colour additive in the United States
The repeal of 21 CFR 74.250 took effect. It was Orange B's only authorised use, so the dye now has no colour additive listing in the United States. The Electronic Code of Federal Regulations shows the section removed as of this date, and no stay of the order has been published.
· United States
FDA revokes the Orange B listing, effective 8 September 2026
The final order at 91 FR 46276 repeals 21 CFR 74.250. FDA's records show Orange B was last batch certified in 1978 and that no certification had been requested since; because a certified colour additive may not be used without certification, FDA concluded the use had been abandoned and the listing was outdated and unnecessary. This was not a safety finding: FDA said the safety of synthetic colour additives in general was outside the scope of the action. Objections were due by 24 August 2026.
· United States
FDA proposes removing the Orange B listing as abandoned
The proposed order at 90 FR 44786 would repeal 21 CFR 74.250, which permitted Orange B for one use only: colouring the casings or surfaces of frankfurters and sausages, at up to 150 parts per million. FDA said certification data showed Orange B had not been certified for use in food marketed in the United States since 1978, so the authorised use appeared to have been abandoned. Comments were invited until 17 October 2025.
What it is made from
A synthetic azo dye made from petroleum-derived aromatic intermediates.
- Vegan
- Vegetarian
Compare other additives on the dietary indexes.
- CAS registry number
- 15139-76-1
- InChIKey
- BLQVZCMYWIKAGV-UHFFFAOYSA-L
- PubChem
- CID 11685735
Every name it appears under
18 recorded names. A label may use any of them.
CAS registry number
- 15139-76-1
As it appears in regulation
- Orange B
Other names
- Acid Orange 137
- BLQVZCMYWIKAGV-UHFFFAOYSA-L
- HSDB 7975
Systematic names
- 1-(4-Sulfophenyl)-3-ethylcarboxy-4-(4-sulfonaphthylazo)-5-hydroxypyrazole disodium
- 1H-Pyrazole-3-carboxylic acid, 4,5-dihydro-5-oxo-4-((4-sulfo-1-naphthalenyl)azo)-1-(4-sulfophenyl)-, 3-ethyl ester, disodi
- 1H-Pyrazole-3-carboxylic acid, 4,5-dihydro-5-oxo-4-((4-sulfo-1-naphthalenyl)azo)-1-(4-sulfophenyl)-, 3-ethyl ester, disodium salt
- 1H-Pyrazole-3-carboxylicacid,4,5-dihydro-5-oxo-4-[2-(4-sulfo-1-naphthalenyl)diazenyl]-1-(4-sulfophenyl)-,3-ethyl ester, sodium salt (1:2)
- 2-Pyrazoline-3-carboxylic acid, 5-oxo-4-((4-sulfo-1-naphthyl)azo)-1-(p-sulfophenyl)-, 2-ethyl ester, disodium salt
- 3-Ethyl 4,5-dihydro-5-oxo-4-((4-sulfo-1-naphthalenyl)azo)-1-(4-sulfophenyl)-1H-pyrazole-3-carboxylate disodium salt
- Disodium 1-(4-sulfophenyl)-3-ethylcarboxy-4-(4-sulfonaphthylazo)-5-hydroxypyrazole
- Disodium 3-ethyl 4,5-dihydro-5-oxo-4-((4-sulfo-1-naphthalenyl)azo)-1-(4-sulfophenyl)-1H-pyrazole-3-carboxylate
- Disodium 3-ethyl 4,5-dihydro-5-oxo-4-((4-sulphonato-1-naphthyl)azo)-1-(4-sulphonatophenyl)-1H-pyrazole-3-carboxylate
- Disodium 3-ethyl 5-oxo-4-((4-sulfo-1-naphthyl)azo)-1-(p-sulfophenyl)-2-pyrazoline-3-carboxylate
- disodium;4-[[3-ethoxycarbonyl-5-oxo-1-(4-sulfonatophenyl)-4H-pyrazol-4-yl]diazenyl]naphthalene-1-sulfonate
- Ethyl 5-oxo-4-(4-sulfonaphthylazo)-1-(p-sulfophenyl)-2-pyrazoline-3-carboxylate disodium salt
- Sodium 4-((3-(ethoxycarbonyl)-5-oxo-1-(4-sulfonatophenyl)-4,5-dihydro-1H-pyrazol-4-yl)diazenyl)naphthalene-1-sulfonate
Hazard reference values
No reference value for this substance in the sources we hold.
Evidence and how bodies read it
Studies, and the differing conclusions regulators drew from them, are curated rather than machine-read, and none has been written for this substance yet.
Common questions
Assembled from what is above, in the words the questions are usually asked in. Each answer is the same statement the relevant section makes, with the same citations behind it.
- What is Orange B?
- Orange B is a synthetic dye that was permitted in the United States for one purpose only: colouring the casings or surfaces of frankfurters and sausages. The FDA revoked that listing with effect from 8 September 2026, finding the use abandoned: Orange B had not been batch certified since 1978. It is not on the EU's list of authorised food additives.
- Is Orange B vegan?
- Yes. Orange B is not derived from animals, and is suitable for vegetarians. This page says what it is made from and how.
Sources for this page
Full licence terms and publisher details on Sources. How this page is built and updated: Method.
Machine-readable: a JSON record of this additive is given on request —how to ask for access.
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