List of IARC Group 2B carcinogens

Substances, mixtures and exposure circumstances in this list have been classified by the IARC as Group 2B: The agent (mixture) is possibly carcinogenic to humans. The exposure circumstance entails exposures that are possibly carcinogenic to humans. This category is used for agents, mixtures and exposure circumstances for which there is limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals. It may also be used when there is inadequate evidence of carcinogenicity in humans but there is sufficient evidence of carcinogenicity in experimental animals. In some instances, an agent, mixture or exposure circumstance for which there is inadequate evidence of carcinogenicity in humans but limited evidence of carcinogenicity in experimental animals together with supporting evidence from other relevant data may be placed in this group. Further details can be found in the IARC Monographs.

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Agents and groups of agents

• A-a-C (2-Amino-9H-pyrido[2,3-b]indole)
• Acetaldehyde
• Acetamide
• Acifluorfen
• Acrylonitrile
• Adapalene
• AF-2 (2-(2-Furyl)-3-(5-nitro-2-furyl)acrylamide)
• Aflatoxin M1
• para-Aminoazobenzene
• ortho-Aminoazotoluene
• 2-Amino-5-(5-nitro-2-furyl)-1,3,4-thiadiazole
• Amsacrine
• ortho-Anisidine
• Antimony trioxide
• Aramite®
• Auramine (technical-grade)
• Azaserine
• Aziridine
• Benzo[b]fluoranthene
• Benzo[j]fluoranthene
• Benzo[k]fluoranthene
• Benzofuran
• Benzyl violet 4B
• 2,2-Bis(bromomethyl)propane-1,3-diol
• Bleomycins
• Bracken fern
• Bromodichloromethane
• Butylated hydroxyanisole
• b-Butyrolactone
• Caffeic acid
• Carbon black
• Carbon tetrachloride
• Catechol
• Chlordane
• Chlordecone (Kepone)
• Chlorendic acid
• para-Chloroaniline
• 3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone
• Chloroform
• 1-Chloro-2-methylpropene
• Chlorophenoxy herbicides
• 4-Chloro-ortho-phenylenediamine
• Chloroprene
• Chlorothalonil
• CI Acid Red 114
• CI Basic Red 9
• CI Direct Blue 15
• Citrus Red No. 2
• Cobalt and cobalt compounds ¹
• Cobalt sulfate and other soluble cobalt(II) salts
• para-Cresidine
• Cycasin
• Dacarbazine
• Dantron (Chrysazin; 1,8-Dihydroxyanthraquinone)
• Daunomycin
• DDT (p,p'-DDT)
• N,N'-Diacetylbenzidine
• 2,4-Diaminoanisole
• 4,4'-Diaminodiphenyl ether
• 2,4-Diaminotoluene
• Dibenz[a,h]acridine
• Dibenz[a,j]acridine
• 7H-Dibenzo[c,g]carbazole
• Dibenzo[a,e]pyrene
• Dibenzo[a,h]pyrene
• Dibenzo[a,i]pyrene
• Dibenzo[a,l]pyrene
• 1,2-Dibromo-3-chloropropane
• 2,3-Dibromopropan-1-ol
• Dichloroacetic acid
• para-Dichlorobenzene
• 3,3'-Dichlorobenzidine
• 3,3'-Dichloro-4,4'-diaminodiphenyl ether
• 1,2-Dichloroethane
• Dichloromethane (methylene chloride)
• 1,3-Dichloropropene (technical-grade)
• Dichlorvos
• 1,2-Diethylhydrazine
• Diglycidyl resorcinol ether
• Dihydrosafrole
• Diisopropyl sulfate
• 3,3'-Dimethoxybenzidine (ortho-Dianisidine)
• para-Dimethylaminoazobenzene
• trans-2-[(Dimethylamino)methylimino]-5-[2-(5-nitro-2-furyl)-vinyl]-1,3,4-oxadiazole
• 2,6-Xylidine (2,6-Dimethylaniline)
• 3,3'-Dimethylbenzidine (ortho-Tolidine)
• 1,1-Dimethylhydrazine
• 3,7-Dinitrofluoranthene
• 3,9-Dinitrofluoranthene
• 1,6-Dinitropyrene
• 1,8-Dinitropyrene
• 2,4-Dinitrotoluene
• 2,6-Dinitrotoluene
• 1,4-Dioxane
• Disperse Blue 1
• 1,2-Epoxybutane
• Ethyl acrylate
• Ethylbenzene
• Ethylene dichloride
• Ethyl methanesulfonate
• Foreign bodies, implanted in tissues

Polymeric, prepared as thin smooth films (with the exception of poly(glycolic acid))

Metallic, prepared as thin smooth films

Metallic cobalt, metallic nickel and an alloy powder containing 66-67% nickel, 13-16% chromium and 7% iron

• 2-(2-Formylhydrazino)-4-(5-nitro-2-furyl)thiazole
• Fumonisin B1
• Furan
• Glu-P-1 (2-Amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole)
• Glu-P-2 (2-Aminodipyrido[1,2-a:3',2'-d]imidazole)
• Glycidaldehyde
• Griseofulvin
• HC Blue No. 1
• Heptachlor
• Hexachlorobenzene
• Hexachloroethane
• Hexachlorocyclohexanes
• Hexamethylphosphoramide (HMPA)
• Human immunodeficiency virus type 2 (infection with)
• Human papillomaviruses: some types other than 16, 18, 31 and 33
• Hydrazine
• 1-Hydroxyanthraquinone
• Indeno[1,2,3-cd]pyrene
• Iron-dextran complex
• Isoprene
• Lasiocarpine
• Lead
• Magenta
• Magnetic fields (extremely low-frequency)
• MeA-a-C (2-Amino-3-methyl-9H-pyrido[2,3-b]indole)
• Medroxyprogesterone acetate
• MeIQ (2-Amino-3,4-dimethylimidazo[4,5-f]quinoline)
• MeIQx (2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline)
• Merphalan
• 2-Methylaziridine (Propyleneimine)
• Methylazoxymethanol acetate
• 5-Methylchrysene
• 4,4'-Methylene bis(2-methylaniline)
• 4,4'-Methylenedianiline
• Methylmercury compounds ¹
• 2-Methyl-1-nitroanthraquinone (uncertain purity)
• N-Methyl-N-nitrosourethane
• Methylthiouracil
• Metronidazole
• Mirex
• Mitomycin C
• Mitoxantrone
• Monocrotaline
• 5-(Morpholinomethyl)-3-[(5-nitrofurfurylidene)amino]-2-oxazolidinone
• Nafenopin
• Naphthalene
• Nickel, metallic and alloys
• Niridazole
• Nitrilotriacetic acid and its salts ¹
• 5-Nitroacenaphthene
• 2-Nitroanisole
• Nitrobenzene
• 6-Nitrochrysene
• Nitrofen (technical-grade)
• 2-Nitrofluorene
• 1-[(5-Nitrofurfurylidene)amino]-2-imidazolidinone
• N-[4-(5-Nitro-2-furyl)-2-thiazolyl]acetamide
• Nitrogen mustard N-oxide
• Nitromethane
• 2-Nitropropane
• 1-Nitropyrene
• 4-Nitropyrene
• N-Nitrosodi-n-butylamine
• N-Nitrosodiethanolamine
• N-Nitrosodi-n-propylamine
• 3-(N-Nitrosomethylamino)propionitrile
• 4-(N-Nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK)
• N-Nitrosomethylethylamine
• N-Nitrosomethylvinylamine
• N-Nitrosomorpholine
• N-Nitrosonornicotine (NNN)
• N-Nitrosopiperidine
• N-Nitrosopyrrolidine
• N-Nitrososarcosine
• Ochratoxin A
• Oestrogen-progestogen therapy, postmenopausal
• Oil Orange SS
• Oxazepam
• Palygorskite (attapulgite) (long fibres, >5 µm)
• Panfuran S (containing dihydroxymethylfuratrizine)
• Phenazopyridine hydrochloride
• Phenobarbital
• Phenolphthalein
• Phenoxybenzamine hydrochloride
• Phenyl glycidyl ether
• Phenytoin
• PhIP (2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine)
• Polychlorophenols and their sodium salts (mixed exposures)
• Ponceau MX
• Ponceau 3R
• Potassium bromate
• Progestins
• Progestogen-only contraceptives
• 1,3-Propane sultone
• b-Propiolactone
• Propylene oxide
• Propylthiouracil
• Refractory ceramic fibres
• Riddelliine
• Safrole
• Schistosoma japonicum (infection with)
• Sodium ortho-phenylphenate
• Special-purpose fibres such as E-glass and '475' glass fibres
• Sterigmatocystin
• Streptozotocin
• Styrene
• Sulfallate
• Tetrafluoroethylene
• Tetranitromethane
• Thioacetamide
• 4,4'-Thiodianiline
• Thiouracil
• Titanium dioxide
• Toluene diisocyanates
• Trichlormethine (Trimustine hydrochloride)
• Trp-P-1 (3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole)
• Trp-P-2 (3-Amino-1-methyl-5H-pyrido[4,3-b]indole)
• Trypan blue
• Uracil mustard
• Urethane
• Vanadium pentoxide
• Vinyl acetate
• 4-Vinylcyclohexene
• 4-Vinylcyclohexene diepoxide
• Zalcitabine
• Zidovudine (AZT)

Mixtures

• Bitumens, extracts of steam-refined and air-refined
• Carrageenan, degraded
• Chlorinated paraffins of average carbon chain length C₁₂ and average degree of chlorination approximately 60%
• Coffee (urinary bladder) ²
• Diesel fuel, marine
• Engine exhaust, gasoline
• Fuel oils, residual (heavy)
• Gasoline
• Pickled vegetables (traditional in Asia)
• Polybrominated biphenyls [Firemaster BP-6, 59536-65-1]
• Toxaphene (Polychlorinated camphenes)
• Toxins derived from Fusarium moniliforme
• Welding fumes

Exposure circumstances

• Carpentry and joinery
• Cobalt metal without tungsten carbide
• Dry cleaning (occupational exposures in)
• Printing processes (occupational exposures in)
• Textile manufacturing industry (work in)

Notes

1. Evaluated as a group.
2. There is some evidence of an inverse relationship between coffee drinking and cancer of the large bowel; coffee drinking could not be classified as to its carcinogenicity to other organs.