IARC group 1 Carcinogens

IARC group 1 Carcinogens are substances, chemical mixtures, and exposure circumstances which have been classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC).^[1] This category is used when there is sufficient evidence of carcinogenicity in humans. Exceptionally, an agent (chemical mixture) may be placed in this category when evidence of carcinogenicity in humans is less than sufficient, but when there is sufficient evidence of carcinogenicity in experimental animals and strong evidence in exposed humans that the agent (mixture) acts through a relevant mechanism of carcinogenicity.

This list focuses on the hazard linked to the agents. This means that while carcinogens are capable of causing cancer, it does not take their risk into account, which is the probability of causing a cancer, given the level of exposure to this carcinogen.^[2] The list is up to date as of January 2024.^[3]

Agents

Infectious conditions

Radiations and physical agents thereof

Ionizing radiation (all types)
Neutron radiation
Phosphorus-32, as phosphate
Plutonium
Radioiodines, including iodine-131
Nuclear fission products, including strontium-90
Radionuclides, α-particle-emitting, internally deposited^{[note 4]}
Radionuclides, β-particle-emitting, internally deposited^{[note 4]}
Radium-224 and its decay products
Radium-226 and its decay products
Radium-228 and its decay products
Radon-222 and its decay products
Solar radiation
Thorium-232 and its decay products
Ultraviolet radiation (wavelengths 100-400 nm, encompassing UVA, UVB, and UVC)
X-ray and gamma radiation

Complex mixtures/agents

Aflatoxins (naturally occurring mixtures of)
Outdoor air pollution
Outdoor air pollution, particulate matter in
Alcoholic beverages
Areca nut, also known as betel nut
Betel quid with or without tobacco
Coal-tar pitch
Coal-tars (see Coal-tar distillation)
Engine exhaust, diesel^[5]
Estrogen-progestogen menopausal therapy (combined)
Estrogen-progestogen oral contraceptives (combined)^{[note 5]}
Estrogen therapy, postmenopausal NB There is "evidence suggesting lack of carcinogenicity" for estrogen-only menopausal therapy in humans and colorectal cancer. An inverse association has been observed between estrogen-only menopausal therapy and cancer of the colorectum.
Leather dust
Mineral oils, untreated or mildly treated
Phenacetin, analgesic mixtures containing
Plants containing aristolochic acid
Polychlorinated biphenyls, dioxin-like, with a Toxicity Equivalency Factor (TEF) according to WHO (PCBs 77, 81, 105, 114, 118, 123, 126, 156, 157, 167, 169, 189)^{[note 6]}
Processed meat (consumption of)^[6]
Salted fish, Chinese-style
Shale-oils
Soot, as found in occupational exposure of chimney sweeps
Wood dust

Exposure circumstances

Acheson process, occupational exposure associated with
Acid mists, strong inorganic
Aluminium production
Auramine production
Boot and shoe manufacture and repair (see Leather dust, Benzene)
Chimney sweeping (see Soot)
Coal gasification
Coal, indoor emissions from household combustion of
Coal-tar distillation
Coke production
Firefighter (occupational exposure as a)
Furniture and cabinet making (see Wood dust)
Haematite mining (underground)
Iron and steel founding (occupational exposure during)
Isopropyl alcohol manufacture using strong acids
Magenta production
Opium consumption
Painter (occupational exposure as a)
Paving and roofing with coal-tar pitch (see Coal-tar pitch)
Rubber manufacturing industry
Tobacco, smokeless
Tobacco smoke, second-hand
Tobacco smoking
Ultraviolet-emitting tanning devices
Welding fumes and UV radiation

Notes

^ This evaluation applies to the group of compounds as a whole and not necessarily to all individual compounds within the group.
^ ^a ^b ^c ^d Evaluated as a group.
^ There is also conclusive evidence that this agent (tamoxifen) reduces the risk of contralateral breast cancer.
^ ^a ^b Specific radionuclides for which there is sufficient evidence for carcinogenicity to humans are also listed individually as Group 1 agents.
^ There is also convincing evidence in humans that these agents confer a protective effect against cancer in the endometrium and ovary.
^ Overall evaluation upgraded to Group 1 with strong supporting evidence from other relevant data.

References

^ "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.
^ "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.
^ "List of Classifications – IARC Monographs on the Identification of Carcinogenic Hazards to Humans". monographs.iarc.who.int. Retrieved 2024-02-01.
^ "IARC Strengthens Its Findings on Several Carcinogenic Personal Habits and Household Exposures" (Press release). International Agency for Research on Cancer (IARC). Retrieved August 1, 2014. November 2, 2009 ‐‐ IARC has updated the cancer assessments of several personal habits and household exposures that cause cancer, including tobacco, areca nut, alcohol, and household coal smoke. The update was conducted with the advice of 30 scientists from 10 countries who met at IARC in October 2009. [...] The Working Group concluded that acetaldehyde associated with alcohol consumption is carcinogenic to humans (Group 1) and confirmed the classification in Group 1 of alcohol consumption and of ethanol in alcoholic beverages.
^ "IARC: Diesel Engine Exhaust Carcinogenic" (Press release). International Agency for Research on Cancer (IARC). Retrieved August 14, 2016. June 12, 2012 ‐‐ After a week-long meeting of international experts, the International Agency for Research on Cancer (IARC), which is part of the World Health Organization (WHO), today classified diesel engine exhaust as carcinogenic to humans (Group 1), based on sufficient evidence that exposure is associated with an increased risk for lung cancer
^ "IARC Monographs evaluate consumption of red meat and processed meat" (PDF). Retrieved 26 October 2015.

External links

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)
- Agents Classified by the IARC Monographs, Volumes 1–123 (Last update: 25 March 2019)

[compunds-5] This evaluation applies to the group of compounds as a whole and not necessarily to all individual compounds within the group.

[evaluated-6] Evaluated as a group.

[7] There is also conclusive evidence that this agent (tamoxifen) reduces the risk of contralateral breast cancer.

[nuclide-8] Specific radionuclides for which there is sufficient evidence for carcinogenicity to humans are also listed individually as Group 1 agents.

[10] There is also convincing evidence in humans that these agents confer a protective effect against cancer in the endometrium and ovary.

[11] Overall evaluation upgraded to Group 1 with strong supporting evidence from other relevant data.

[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] "List of Classifications – IARC Monographs on the Identification of Carcinogenic Hazards to Humans". monographs.iarc.who.int. Retrieved 2024-02-01.

[FOOTNOTEIARC20091102-4] "IARC Strengthens Its Findings on Several Carcinogenic Personal Habits and Household Exposures" (Press release). International Agency for Research on Cancer (IARC). Retrieved August 1, 2014. November 2, 2009 ‐‐ IARC has updated the cancer assessments of several personal habits and household exposures that cause cancer, including tobacco, areca nut, alcohol, and household coal smoke. The update was conducted with the advice of 30 scientists from 10 countries who met at IARC in October 2009. [...] The Working Group concluded that acetaldehyde associated with alcohol consumption is carcinogenic to humans (Group 1) and confirmed the classification in Group 1 of alcohol consumption and of ethanol in alcoholic beverages.

[PRDEE-9] "IARC: Diesel Engine Exhaust Carcinogenic" (Press release). International Agency for Research on Cancer (IARC). Retrieved August 14, 2016. June 12, 2012 ‐‐ After a week-long meeting of international experts, the International Agency for Research on Cancer (IARC), which is part of the World Health Organization (WHO), today classified diesel engine exhaust as carcinogenic to humans (Group 1), based on sufficient evidence that exposure is associated with an increased risk for lung cancer

[12] "IARC Monographs evaluate consumption of red meat and processed meat" (PDF). Retrieved 26 October 2015.

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v t e Cancer-causing materials and agents (carcinogens)
Cancer Cancer cells
Prominent human carcinogens	Acetaldehyde Arsenic Asbestos Bacteria Helicobacter pylori Benzo[a]pyrene 1,3-Butadiene Diethylstilbestrol Formaldehyde Ionizing radiation (e.g., from isotopes of plutonium and radium) Tobacco smoke Ultraviolet light Viruses Epstein–Barr Hepatitis B Hepatitis C HPV
IARC lists	Group 1 (carcinogenic) Group 2A (probably carcinogenic) Group 2B (possibly carcinogenic) Group 3 (not classifiable)

Agents

Infectious conditions

Viruses

Bacterium

Worms

Chemical substances