Orange B

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.^[1] It is typically prepared as a disodium salt.^[1]

Orange B

Names
IUPAC name Disodium 4-[N'-[3-ethoxycarbonyl-5-oxo-1-(4-sulfonatophenyl)-4-pyrazolylidene]hydrazino]-1-naphthalenesulfonate
Other names C.I. Acid Orange 137; CI 19235
Identifiers
CAS Number	15139-76-1 Y
3D model (JSmol)	Interactive image
ChemSpider	16735944 Y
ECHA InfoCard	100.035.622
EC Number	239-201-5
PubChem CID	5362511
UNII	RGU455OS50 Y
CompTox Dashboard (EPA)	DTXSID7044219
InChI InChI=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+;; Y Key: LLTKITSFUJSOCC-KPOOZVEVSA-L Y 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+;; Key: LLTKITSFUJSOCC-AQVGDJFIBI
SMILES [Na+].[Na+].[O-]S(=O)(=O)c4ccc(/N=N/c2c(nn(c1ccc(cc1)S([O-])(=O)=O)c2O)C(=O)OCC)c3ccccc34
Properties
Chemical formula	C22H16N4Na2O9S2
Molar mass	590.49 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

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.^[2]

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.^[3]