Table 1.
Agents that the International Agency for Research on Cancer has classified as carcinogenic to humans and associated cancer sites
| Carcinogenic agent | Cancer sites with sufficient evidence in humans* | Cancer sites with limited evidence in humans | Earlier volumes that classified the agent as carcinogenic† |
| Chemicals and mixtures | |||
| Acid mists, strong inorganic | Larynx | Lung | 54 (1992) |
| Aflatoxins | Liver (hepatocellular carcinoma) | Suppl 7 (1987); 56 (1993); 82 (2002) | |
| 4-Aminobiphenyl | Urinary bladder | 1 (1972); 99 (2010) | |
| Aristolochic acid‡ | Renal pelvis; ureter | § | |
| Aristolochic acid, plants containing | Renal pelvis; ureter | 82 (2002) | |
| Benzene | Leukemia (acute nonlymphocytic) | Leukemia (acute lymphocytic, chronic lymphocytic, multiple myeloma, non-Hodgkin lymphoma) | 7 (1974); 29 (1982) |
| Benzidine | Urinary bladder | 1 (1972); 29 (1982); 99 (2010) | |
| Benzidine, dyes metabolized to‡ | 99 (2010) | ||
| Benzo[a]pyrene‡ | 92 (2010) | ||
| Bis(chloromethyl)ether; chloromethyl methyl ether (technical grade) | Lung | 4 (1974) | |
| 1,3-Butadiene | Hematolymphatic organs | 97 (2008) | |
| Coal tar pitch | Lung*; skin | Urinary bladder | 3 (1973); 35 (1985) |
| Ethylene oxide‡ | Breast; lymphoid tumors (non-Hodgkin lymphoma, multiple myeloma, chronic lymphocytic leukemia) | 60 (1994); 97 (2008) | |
| Formaldehyde | Leukemia (particularly myeloid)*; nasopharynx | Nasal cavity and paranasal sinus | 88 (2006) |
| 4,4′-Methylenebis(2-chloroaniline) (MOCA)‡ | 99 (2010) | ||
| Mineral oils, untreated or mildly treated | Skin | 3 (1973); 33 (1984) | |
| 2-Naphthylamine | Urinary bladder | 4 (1974); 99 (2010) | |
| Tobacco-specific nitrosamines: N′-nitrosonornicotine (NNN) and 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK)‡ | 89 (2007) | ||
| Shale oils | Skin | 3 (1973); 35 (1985) | |
| Soot | Lung*; skin | Urinary bladder | 3 (1973); 35 (1985) |
| Sulfur mustard | Lung | Larynx | 9 (1975) |
| 2,3,7,8-Tetrachlorodibenzo-para-dioxin | All cancers combined | Lung; non-Hodgkin lymphoma; soft tissue sarcoma | 69 (1997) |
| 3,4,5,3’,4’-Pentachlorobiphenyl (PCB-126)‡ | § | ||
| 2,3,4,7,8-Pentachlorodibenzofuran‡ | § | ||
| Ortho-Toluidine | Urinary bladder | 99 (2010) | |
| Vinyl chloride | Liver (angiosarcoma, hepatocellular carcinoma) | 7 (1974); 19 (1979); 97 (2008) | |
| Occupations | |||
| Aluminum production | Lung; urinary bladder | Sup 7 (1987); 92 (2010) | |
| Auramine production | Urinary bladder | 1 (1972); 99 (2010) | |
| Coal gasification | Lung | 34 (1984); 92 (2010) | |
| Coal tar distillation | Skin | 34 (1984); 92 (2010) | |
| Coke production | Lung | 34 (1984); 92 (2010) | |
| Hematite mining (underground)‖ | Lung | 1 (1972) | |
| Iron and steel founding | Lung | Sup 7 (1987) | |
| Isopropyl alcohol production | Nasal cavity and paranasal sinus | 15 (1977) | |
| Magenta production | Urinary bladder | Sup 7 (1987); 57 (1993); 99 (2010) | |
| Painting | Lung; mesothelioma*; urinary bladder* | Maternal exposure: childhood leukemia | 47 (1989); 98 (2010) |
| Rubber production industry | Leukemia, lymphoma; lung; stomach; urinary bladder | Larynx; esophagus; prostate | 28 (1982) |
| Welding¶ | Eye (melanoma) | § | |
| Metals | |||
| Arsenic and inorganic arsenic compounds | Lung*; skin; urinary bladder* | Kidney; liver; prostate | 2 (1973); 23 (1980); 84 (2004) |
| Beryllium and beryllium compounds | Lung | 58 (1993) | |
| Cadmium and cadmium compounds | Lung | Kidney; prostate | 58 (1993) |
| Chromium (VI) compounds# | Lung | Nasal cavity and paranasal sinus | 2 (1973); 23 (1980); 49 (1990) |
| Nickel compounds** | Lung; nasal cavity and paranasal sinus | 2 (1973); 11 (1976); 49 (1990) | |
| Dusts and fibers | |||
| Asbestos (all forms) | Larynx*; lung; mesothelioma; ovary* | Colorectum; pharynx; stomach | 2 (1973); 14 (1977) |
| Erionite | Mesothelioma | 42 (1987) | |
| Leather dust†† | Nasal cavity and paranasal sinus | 25 (1981) | |
| Silica dust, crystalline (in the form of quartz or crystobalite) | Lung | 68 (1997) | |
| Wood dust‡‡ | Nasal cavity and paranasal sinus; nasopharynx* | 25 (1981); 62 (1995) | |
| Radiation | |||
| Ionizing radiation (all types)§§ | § | ||
| Alpha-particle emitters§§ | 78 (2001) | ||
| Radon-222 and its decay products | Lung | Leukemia | 43 (1988) |
| Radium-224 and its decay products | Bone | 78 (2001) | |
| Radium-226 and its decay products | Bone; mastoid process; paranasal sinus | 78 (2001) | |
| Radium-228 and its decay products | Bone; mastoid process*; paranasal sinus* | 78 (2001) | |
| Thorium-232 and its decay products | Bile duct, extrahepatic*; gall bladder*; leukemia (excluding chronic lymphocytic leukemia); liver (including hemangiosarcoma) | Pancreas; prostate | 78 (2001) |
| Plutonium | Bone; liver; lung | Other solid tumors | 78 (2001) |
| Beta-particle emitters§§ | 78 (2001) | ||
| Phosphorus-32 | Leukemia (acute) | 78 (2001) | |
| Fission products, including Strontium-90 | Leukemia; solid cancers | § | |
| Radioiodines, including Iodine-131 | Thyroid | Bone and soft tissue; digestive tract; leukemia; salivary gland | 78 (2001) |
| X radiation, gamma radiation | Bone*; brain and central nervous system*; breast (female); colon; kidney*; leukemia (excluding chronic lymphocytic leukemia); lung*; esophagus*; salivary gland*; skin (basal cell carcinoma)*; stomach; thyroid; urinary bladder*; exposure in utero: multiple sites* | Liver; multiple myeloma; non-Hodgkin lymphoma; ovary; pancreas; prostate; rectum | 75 (2000) |
| Neutron radiation‡ | 75 (2000) | ||
| Solar radiation | Skin (basal cell carcinoma, squamous cell carcinoma, melanoma) | Eye (squamous cell carcinoma, melanoma); lip | 55 (1992) |
| Ultraviolet radiation‡ | § | ||
| Ultraviolet-emitting tanning devices | Eye (melanoma); skin (melanoma) | Skin (squamous cell carcinoma) | § |
| Biological agents | |||
| Epstein–-Barr virus | Burkitt lymphoma; Hodgkin lymphoma; lymphoma (extranodal NK/T-cell, nasal type); nasopharynx; non-Hodgkin lymphoma (immune suppression related) | Lymphoepithelial-like carcinoma; stomach | 70 (1997) |
| Hepatitis B virus | Liver (hepatocellular carcinoma) | Liver (cholangiocarcinoma); non-Hodgkin lymphoma | 59 (1994) |
| Hepatitis C virus | Liver (hepatocellular carcinoma); non-Hodgkin lymphoma* | Liver (cholangiocarcinoma) | 59 (1994) |
| HIV type 1 | Anus*; cervix*; eye (conjunctiva)*; Hodgkin lymphoma*; Kaposi sarcoma; non-Hodgkin lymphoma | Liver (hepatocellular carcinoma); penis; skin (non-melanoma); vagina; vulva | 67 (1996) |
| Human papillomavirus type 16 | Anus; cervix; oral cavity*; oropharynx*; penis*; tonsil*; vagina*; vulva* | Larynx | 64 (1995); 90 (2007) |
| Human papillomavirus type 18 | Cervix | Anus; larynx; oral cavity; penis; vulva | 64 (1995); 90 (2007) |
| Human papillomavirus type 33 | Cervix | Anus; vulva | 90 (2007) |
| Human papillomavirus types 31, 35, 39, 45, 51, 52, 56, 58, 59 | Cervix | 90 (2007) | |
| Human T-cell lymphotropic virus type 1 | Leukemia and/or lymphoma (adult T-cell) | 67 (1996) | |
| Kaposi sarcoma herpes virus | Kaposi sarcoma; lymphoma (primary effusion) | Lymph nodes (multicentric Castleman disease) | § |
| Clonorchis sinensis | Liver (cholangiocarcinoma) | § | |
| Helicobacter pylori | Lymphoma (low-grade B-cell mucosa-associated lymphoid-tissue gastric lymphoma); stomach (noncardia carcinoma) | 61 (1994) | |
| Opisthorchis viverrini | Liver (cholangiocarcinoma) | 61 (1994) | |
| Schistosoma haematobium | Urinary bladder | 61 (1994) | |
| Personal habits | |||
| Alcoholic beverages | Breast (female)*; colorectum*; larynx; liver (hepatocellular carcinoma); esophagus; oral cavity; pharynx | Pancreas | 44 (1988); 96 (2010) |
| Acetaldehyde associated with consumption of alcoholic beverages | Aerodigestive tract, upper; esophagus | § | |
| Ethanol in alcoholic beverages‡ | 96 (2010) | ||
| Areca nut‡ | 85 (2004) | ||
| Betel quid with tobacco | Esophagus*; oral cavity; pharynx* | 37 (1985); 85 (2004) | |
| Betel quid without tobacco | Esophagus*; oral cavity | Liver | 85 (2004) |
| Coal, indoor emissions from household combustion | Lung | 95 (2010) | |
| Salted fish, Chinese style | Nasopharynx | Stomach | 56 (1993) |
| Tobacco smoking | Bone marrow (myeloid leukemia)*; cervix*; colorectum*; kidney (body, renal pelvis); larynx; liver*; lung; nasal cavity and paranasal sinus*; esophagus (adenocarcinoma, squamous cell carcinoma); oral cavity; ovary (mucinous)*; pancreas; pharynx (nasopharynx, oropharynx, hypopharynx); stomach*; ureter*; urinary bladder; in smokers’ children: hepatoblastoma* | Breast; in smokers’ children: childhood leukemia (particularly acute lymphocytic) | 38 (1986); 83 (2004) |
| Tobacco smoke, secondhand | Lung | Larynx; pharynx | 83 (2004) |
| Tobacco, smokeless | Esophagus*; oral cavity; pancreas* | 37 (1985); 89 (2007) | |
| Pharmaceuticals | |||
| Azathioprine | Non-Hodgkin lymphoma; skin (squamous cell carcinoma) | 26 (1981) | |
| Busulfan | Leukemia (acute myeloid) | Sup 4 (1982) | |
| Chlorambucil | Leukemia (acute myeloid) | Sup 7 (1987) | |
| Chlornaphazine | Urinary bladder | 4 (1974) | |
| Cyclophosphamide | Leukemia (acute myeloid)*; urinary bladder | 26 (1981) | |
| Cyclosporine | Non-Hodgkin lymphoma; skin (non-melanocytic)*; multiple other sites* | 50 (1990) | |
| Diethylstilbestrol | Exposure during pregnancy: breast*; exposure in utero: cervix (clear cell adenocarcinoma) and vagina (clear cell adenocarcinoma) | Exposure during pregnancy: endometrium; exposure in utero: cervix (squamous cell carcinoma) and testis | 6 (1974); 21 (1979) |
| Estrogen menopausal therapy | Endometrium; ovary* | Breast | 21 (1979); 72 (1999) |
| Estrogen–progestogen contraceptives (combined) | Breast*; cervix*; liver (hepatocellular carcinoma); note: reduced risk in endometrium, ovary | 72 (1999); 91 (2007) | |
| Estrogen–progestogen menopausal therapy (combined) | Breast; endometrium (estrogen-induced risk decreases with number of days/month of progestogen use) | 91 (2007) | |
| Etoposide‡ | Leukemia (acute myeloid) | § | |
| Etoposide with cisplatin and bleomycin | Leukemia (acute myeloid) | 76 (2000) | |
| Melphalan | Leukemia (acute myeloid) | Sup 1 (1979) | |
| Methoxsalen plus ultraviolet A | Skin (squamous cell carcinoma) | 24 (1980) | |
| MOPP (vincristine-prednisone-nitrogen mustard-procarbazine mixture) | Leukemia (acute myeloid); lung* | 26 (1987) | |
| Phenacetin | Renal pelvis; ureter | § | |
| Phenacetin, analgesic mixtures containing | Renal pelvis; ureter* | Sup 4 (1982) | |
| Semustine (methyl-CCNU) | Leukemia (acute myeloid) | Sup 7 (1987) | |
| Tamoxifen | Endometrium; note: reduced risk in contralateral breast of breast cancer patients | 66 (1996) | |
| Thiotepa | Leukemia | 50 (1990) | |
| Treosulfan | Leukemia (acute myeloid) | 26 (1981) | |
Sufficient evidence became available for marked sites in this column after the agent had been classified as 'carcinogenic' in an earlier volume.
Each agent was classified as carcinogenic to humans in Volume 100 (2011); to save space, Volume 100 is not listed in this column. In addition, Supplements 1 (1979), 4 (1982), and 7 (1987) updated all earlier volumes; supplements are listed only if a causal relationship was first established in the supplement.
Aristolochic acid, ethylene oxide, and etoposide are classified as carcinogenic to humans with limited evidence from studies of cancer in humans but strong mechanistic evidence in exposed humans; thus, there are no cancer sites with sufficient evidence. Dyes metabolized to benzidine; benzo[a]pyrene; 4,4′-methylenebis(2-chloroaniline) (MOCA); N′-nitrosonornicotine (NNN) and 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK); 3,4,5,3′4′-pentachlorobiphenyl (PCB-126); 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-PCDF); neutron radiation, ultraviolet radiation, ethanol in alcoholic beverages, and areca nut are classified as carcinogenic to humans with inadequate evidence from studies of cancer in humans but strong mechanistic evidence in exposed humans; thus, there are no cancer sites with sufficient evidence or limited evidence.
Classified as carcinogenic to humans for the first time in Volume 100.
Potential causal agents include radon, crystalline silica dust, and diesel engine emissions.
Volume 100 concluded that there is sufficient evidence for ocular melanoma in welders but left formal reclassification in Group 1 for a future volume that would consider all exposures during welding. Causal agents were not identified (See also “Welding fumes” in Table 3).
In Volume 2, the conclusion was for chromate production; in Supplement 1, the evaluation was more specifically for chromium and certain chromium compounds; in Supplement 7, for chromium (VI) compounds.
In Volume 2, the conclusion was for nickel refining; in volume 49, the evaluation was more specifically for nickel compounds.
In Volume 25, the conclusion was that nasal adenocarcinoma and leukemia are causally associated with employment in the boot and shoe industry; in Volume 100, the leukemias were attributed to benzene, and a new evaluation was made for leather dust as the causal agent for the nasal cancers.
In Volume 25, the conclusion was for employment in the furniture-making industry; in Volumes 62 and 100, the evaluation was made specifically for wood dust.
Umbrella term encompassing several radionuclides listed next; no additional cancer sites were identified.