Congo Red

Agent Name
Congo Red
CAS Number
Major Category
Congo Red formula graphical representation
1-Naphthalenesulfonic acid, 3,3'-((1,1'-biphenyl)-4,4'-diylbis(azo))bis(4-amino-, disodium salt; Atlantic Congo Red; Atul Congo Red; Azocard Red Congo; Benzo Congo Red; Brasilamina congo 4B; C.I. 22120; C.I. Direct Red 28; C.I. Direct Red 28, disodium salt; Cerven kongo [Czech]; Cerven prima 28 [Czech]; Congazone sodium; Congo Red; Congo Red 4B; Congo Red 4BX; Congo Red CR; Congo Red H; Congo Red ICI; Congo Red L; Congo Red M; Congo Red N; Congo Red R; Congo Red W; Congo Red WS; Cotton Red 4BC; Cotton Red 5B; Cotton Red L; Diacotton Congo Red; Direct Red 28; Direct Red C; Direct Red DC-CF; Direct Red K; Erie Congo 4B; Haemomedical; Haemonorm; Hemorrhagyl; Hispamin congo 4B; Kayaku Congo Red; Kongorot [German]; Mitsui Congo Red; Natrium-salz der diphenyl-bis-azo-bis-naphthylamin-4-sulfonsaeure [German]; Peeramine Congo Red; Red K; Sodium diphenyldiazo-bis(alpha-naphthylaminesulfonate); Solucongo; Sugai Congo Red; Tertrodirect Red C; Trisulfon Congo Red; Vondacel Red CL; 1-Naphthalenesulfonic acid, 3,3'-(4,4'-biphenylenebis(azo))bis(4-amino-, disodium salt; Disodium 3,3'-((1,1'-biphenyl)-4,4'-diylbis(azo))bis(4-aminonaphthalene-1-sulphonate); [ChemIDplus]
Benzidine Dyes
Red to red-brown solid; [ChemIDplus] Yellowish-red in water or orange in ethanol; [HSDB]
Used in medical diagnosis (amyloidosis) and treatment (antihemolytic and detoxicant); [ChemIDplus] Used to dye cotton, wool, and paper; Also used as a gelling agent for poly(vinyl alcohol); [HSDB]
May cause anaphylaxis; [PMID 14185855] One of the azo dyes metabolized to benzidine--known to be a human carcinogen; [NTP]
Biomedical References

Exposure Assessment

Vapor Pressure
2.24E-30 mm Hg
Lethal Concentration
LCLo (rat) = 50,000 mg/m3/1h

Adverse Effects

NTP Carcinogen
Human carcinogen

Diseases, Processes, and Activities Linked to This Agent


Industrial Processes with risk of exposure: