Orange B
{{Globalize|US-centric article|date=April 2025}}
{{Chembox
| Verifiedfields = changed
| verifiedrevid = 470456447
| ImageFile = Acid Orange 137.png
| ImageSize = 196px
| ImageFile1 = Orange B ball-and-stick.png
| ImageSize1 = 196px
| IUPACName = Disodium 4-[N'-[3-ethoxycarbonyl-5-oxo-1-(4-sulfonatophenyl)-4-pyrazolylidene]hydrazino]-1-naphthalenesulfonate
| OtherNames = C.I. Acid Orange 137; CI 19235
| Section1 = {{Chembox Identifiers
| InChI = 1/C22H18N4O9S2.2Na/c1-2-35-22(28)20-19(21(27)26(25-20)13-7-9-14(10-8-13)36(29,30)31)24-23-17-11-12-18(37(32,33)34)16-6-4-3-5-15(16)17;;/h3-12,27H,2H2,1H3,(H,29,30,31)(H,32,33,34);;/q;2*+1/p-2/b24-23+;;
| InChIKey = LLTKITSFUJSOCC-AQVGDJFIBI
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C22H18N4O9S2.2Na/c1-2-35-22(28)20-19(21(27)26(25-20)13-7-9-14(10-8-13)36(29,30)31)24-23-17-11-12-18(37(32,33)34)16-6-4-3-5-15(16)17;;/h3-12,27H,2H2,1H3,(H,29,30,31)(H,32,33,34);;/q;2*+1/p-2/b24-23+;;
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = LLTKITSFUJSOCC-KPOOZVEVSA-L
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 15139-76-1
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = RGU455OS50
| EINECS=239-201-5
| PubChem=5362511
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID=16735944
| SMILES = [Na+].[Na+].[O-]S(=O)(=O)c4ccc(/N=N/c2c(nn(c1ccc(cc1)S([O-])(=O)=O)c2O)C(=O)OCC)c3ccccc34
}}
| Section2 = {{Chembox Properties
| Formula=C22H16N4Na2O9S2
| MolarMass=590.49 g/mol
| Appearance=
| Density=
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| BoilingPt=
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| Section3 = {{Chembox Hazards
| MainHazards=
| FlashPt=
| AutoignitionPt =
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Orange B is a food dye from the azo dye group. It is approved by the United States Food and Drug Administration (FDA) for use only in hot dog and sausage casings or surfaces, up to 150 parts per million of the finished food weight.{{cite web|title=Code of Federal Regulations: Title 21, Section 74.250|url=https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfCFR/CFRSearch.cfm?fr=74.250|publisher=U.S. Food and Drug Administration|access-date=24 December 2012}} It is typically prepared as a disodium salt.
Orange B was first approved by the FDA for use as a certified food dye in 1966. However, in 1978, the FDA proposed removing it from the list of approved food additives due to concerns over potential carcinogenic contaminants, particularly the presence of 2-naphthylamine. Around the same time, its sole U.S. manufacturer, the William J. Stange Company, ceased production. Despite its non-use in food products since the late 20th century, the FDA did not formally revoke its approval.{{cite book|last=Hathcock|first=John N.|title=Nutritional Toxicology|date=1982|publisher=Academic Press|location=New York|isbn=012332601X|pages=407–408}}
On April 22, 2025, the FDA announced plans to phase out synthetic food dyes by the end of 2026. This decision, led by FDA Commissioner Martin Makary, was driven by growing concerns over the potential health risks associated with synthetic food dyes. As part of this phase-out, the FDA revealed its intention to revoke approval for Orange B, along with another restricted-use dye, Citrus Red 2.{{Cite web |last=Choi |first=Joseph |date=2025-04-22 |title=FDA announces plans to phase out petroleum-based food dyes |url=https://thehill.com/policy/healthcare/5261583-fda-phases-out-petroleum-food-dyes/ |access-date=2025-04-24 |website=The Hill}}