IARC group 2B

Substances, mixtures and exposure circumstances in this list have been classified by the International Agency for Research on Cancer (IARC) as group 2B:^[1] 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 preamble to the IARC Monographs.

This list is focusing on the hazard linked to the agents. This means that the carcinogenic agents are capable of causing cancer, but this does not take their risk into account, which is the probability of causing a cancer given the level of exposure to this carcinogenic agent.^[2]

Agents and groups of agents

A

• A-α-C (2-Amino-9H-pyrido[2,3-b]indole)
• Acetaldehyde
• Acetamide
• Acrylonitrile
• AF-2 (2-(2-Furyl)-3-(5-nitro-2-furyl)acrylamide)
• Aflatoxin M1
• 1-Amino-2,4-dibromoanthraquinone
• para-Aminoazobenzene
• ortho-Aminoazotoluene
• 2-Amino-5-(5-nitro-2-furyl)-1,3,4-thiadiazole
• Amsacrine
• ortho-Anisidine
• Aspartame

B

• Benz[j]aceanthrylene
• Benz[a]anthracene
• Benzo[b]fluoranthene
• Benzo[j]fluoranthene
• Benzo[k]fluoranthene
• Benzo[c]phenanthrene
• Benzophenone
• Benzofuran
• Benzyl violet 4B
• 2,2-Bis(bromomethyl)propane-1,3-diol
• BK polyomavirus (BKV)
• Bleomycin
• Bracken fern
• Bromochloroacetic acid
• Bromodichloromethane
• 1-Bromopropane
• Butylated hydroxyanisole
• β-Butyrolactone

C

• Caffeic acid
• Carbazole
• Carbon black
• Carbon nanotubes, multi-walled MWCNT-7
• Carbon tetrachloride
• Catechol
• Chlordane
• Chlordecone (Kepone)
• Chlorendic acid
• para-Chloroaniline
• 3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone
• Chloroform
• 1-Chloro-2-methylpropene
• 3-Chloro-2-methylpropene, technical grade
• Chlorophenoxy herbicides
• 4-Chloro-ortho-phenylenediamine
• Chloroprene
• Chlorothalonil
• Chrysene
• 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
• Coconut oil diethanolamine condensate
• para-Cresidine
• Cumene
• Cycasin

D

• 2,4-D (2,4-dichlorophenoxyacetic acid)
• 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[c,h]acridine
• 7H-Dibenzo[c,g]carbazole
• Dibenzo[a,e]pyrene
• Dibenzo[a,h]pyrene
• Dibenzo[a,i]pyrene
• Dibromoacetic acid
• Dibromoacetonitrile
• 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
• 1,3-Dichloropropene (technical grade)
• 1,3-Dichloro-2-propanol
• Dichlorvos
• Diethanolamine
• Di(2-ethylhexyl)phthalate
• 1,2-Diethylhydrazine
• Diglycidyl resorcinol ether
• Digoxin
• Dihydrosafrole
• Diisopropyl sulfate
• 3,3'-Dimethoxybenzidine (o-Dianisidine)
• para-Dimethylaminoazobenzene
• trans-2-[(Dimethylamino)methylimino]-5-[2-(5-nitro-2-furyl)-vinyl]-1,3,4-oxadiazole
• 2,6-Xylidine (2,6-Dimethylaniline)
• Dimethylarsinic acid
• 3,3'-Dimethylbenzidine (o-Tolidine)
• 1,1-Dimethylhydrazine
• Dimethyl-p-toluidine
• 3,7-Dinitrofluoranthene
• 3,9-Dinitrofluoranthene
• 1,3-Dinitropyrene
• 1,6-Dinitropyrene
• 1,8-Dinitropyrene
• 2,4-Dinitrotoluene
• 2,6-Dinitrotoluene
• 1,4-Dioxane
• Disperse Blue 1

E

• 1,2-Epoxybutane
• Ethyl acrylate
• Ethylbenzene
• Ethylene dichloride
• Ethyl methanesulfonate

F

• 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

G

• Ginkgo biloba extract
• 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

H

• HC Blue No. 1
• Heptachlor
• Hexachlorobenzene
• Hexachloroethane
• Hexachlorocyclohexanes
• Hexamethylphosphoramide (HMPA)
• 2,4-Hexadienal
• Human immunodeficiency virus type 2 (infection with)
• Human papillomavirus types 26, 53, 66, 67, 70, 73, 82
• Human papillomavirus types 30, 34, 69, 85, 97
• Human papillomavirus types 5 and 8 (in patients with epidermodysplasia verruciformis)
• Hydrochlorothiazide
• 1-Hydroxyanthraquinone

I

• Indeno[1,2,3-cd]pyrene
• Indium tin oxide
• Iron-dextran complex
• Isoprene

J

• JC polyomavirus (JCV)

K

• Kava extract

L

• Lasiocarpine
• Lead

M

• Magnetic fields (extremely low frequency)
• MeA-α-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)
• Melamine
• Merphalan
• Methylarsonic acid
• 2-Methylaziridine (Propyleneimine)
• Methylazoxymethanol acetate
• 5-Methylchrysene
• 4,4'-Methylene bis(2-methylaniline)
• 4,4'-Methylenedianiline
• Methyleugenol
• 2-Methylimidazole
• 4-Methylimidazole
• Methyl isobutyl ketone
• Methylmercury compounds ¹
• 2-Methyl-1-nitroanthraquinone (uncertain purity)
• N-Methyl-N-nitrosourethane
• Methylthiouracil
• α-Methylstyrene
• Metronidazole
• Michler's base (4,4'-methylene-bis(N,N-dimethyl)benzenamine)
• Michler's ketone (4,4'-bis(dimethylamino)benzophenone)
• Microcystin-LR
• Mirex
• Mitomycin C
• Mitoxantrone
• Molybdenum trioxide
• 3-Monochloro-1,2-propanediol (3-MCPD)
• Monocrotaline
• 5-(Morpholinomethyl)-3-[(5-nitrofurfurylidene)amino]-2-oxazolidinone
• β-Myrcene

N

• Nafenopin
• Naphthalene
• Nickel, metallic and alloys
• Niridazole
• Nitrilotriacetic acid and its salts ¹
• 5-Nitroacenaphthene
• 2-Nitroanisole
• 3-Nitrobenzanthrone
• Nitrobenzene
• 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
• 4-Nitropyrene
• N-Nitrosodi-n-butylamine
• N-Nitrosodiethanolamine
• N-Nitrosodi-n-propylamine
• 3-(N-Nitrosomethylamino)propionitrile
• N-Nitrosomethylethylamine
• N-Nitrosomethylvinylamine
• N-Nitrosomorpholine
• N-Nitrosopiperidine
• N-Nitrosopyrrolidine
• N-Nitrososarcosine

O

• Ochratoxin A
• Oil Orange SS
• Oxazepam

P

• Palygorskite (attapulgite) (long fibres, >5 µm)
• Panfuran S (containing dihydroxymethylfuratrizine)
• Parathion
• Pentosan polysulfate sodium
• Perfluorooctanoic acid
• 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
• Primidone
• Progestins
• Progestogen-only contraceptives
• β-Propiolactone
• Propylene oxide
• Propylthiouracil
• Pulegone
• Pyridine

Q

• Quinoline

R

• Radiofrequency electromagnetic fields, such as, but not limited to, those associated with wireless phones^[3]
• Refractory ceramic fibres
• Riddelliine

S

• Safrole
• Schistosoma japonicum (infection with)
• Silicon carbide, fibrous
• Sodium ortho-phenylphenate
• Special-purpose fibres such as E-glass and '475' glass fibres
• Sterigmatocystin
• Streptozotocin
• Sulfasalazine
• Sulfallate

T

• 1,1,1,2-Tetrachloroethane
• 1,1,2,2-Tetrachloroethane
• Tetrachlorvinphos
• Tetrahydrofuran
• Tetranitromethane
• Thioacetamide
• 4,4'-Thiodianiline
• 2-Thiouracil
• Titanium dioxide
• Toluene diisocyanates
• Toxaphene (Polychlorinated camphenes)
• Triamterene
• Trichlormethine (Trimustine hydrochloride)
• Trichloroacetic acid
• 2,4,6-Trichlorophenol
• 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

U

• Uracil mustard

V

• Vanadium pentoxide
• Vinyl acetate
• 4-Vinylcyclohexene
• 4-Vinylcyclohexene diepoxide

Z

• Zalcitabine
• Zidovudine (AZT)

Mixtures

• Aloe vera, whole leaf extract
• Bitumens, occupational exposure to straight-run bitumens and their emissions during road paving
• Bitumens, occupational exposure to hard bitumens and their emissions during mastic asphalt work
• Carrageenan, degraded (Poligeenan)
• Chlorinated paraffins of average carbon chain length C₁₂ and average degree of chlorination approximately 60%
• Diesel fuel, marine
• Engine exhaust, gasoline
• Fuel oils, residual (heavy)
• Fusarium moniliforme, toxins derived from (fumonisin B₁, fumonisin B₂, and fusarin C)
• Gasoline
• Goldenseal root powder
• Magenta dyes (CI Basic Red and fuchins)
• Pickled vegetables (traditional in Asia)
• Toxaphene (Polychlorinated camphenes)
• Welding fumes

Exposure circumstances

• Carpentry and joinery
• Cobalt metal without tungsten carbide
• Dry cleaning (occupational exposures in)
• Firefighter (occupational exposure as)
• Printing processes (occupational exposures in)
• Talc-based body powder (perineal use of)
• Textile manufacturing industry (work in)

Notes

• ^1 Evaluated as a group.

References

1. "List of Classifications, Agents classified by the IARC Monographs, Volumes 1–124". IARC Monographs on the Evaluation of Risk to Humans. IARC. July 7, 2019. Retrieved July 14, 2019.
2. "IARC monographs preamble (as amended in 2019)" (PDF). International Agency for Research on Cancer (IARC). Retrieved August 18, 2023. A cancer hazard is an agent that is capable of causing cancer, whereas a cancer risk is an estimate of the probability that cancer will occur given some level of exposure to a cancer hazard.
3. Press release No 208, 31 May 2011, IARC classifies Radiofrequency Electromagnetic Fields as possibly carcinogenic to humans

External links

 

Wikimedia Commons has media related to IARC Group 2B carcinogens.

• Description of the list of classifications, IARC
  • List of Classifications (latest version)
  • List of Classifications by cancer sites with sufficient or limited evidence in humans, Volumes 1 to 124 (Last update: 8 July 2019)