What is IARC Group 3?
Group 3 — not classifiable. 413 factors in the Meyron reference are currently classified this way.
Plain-language explanation
Not enough reliable evidence yet to say whether this causes cancer. This does NOT mean it is safe — it means science has not answered the question.
Examples
1-Amino-2-methylanthraquinone
Mostly industrial — used as a dye in textiles, leather, paper, or research. Some are or were used in cosmetics or food colouring; check the specific entry.
1-Methylchrysene
Breathed and eaten. Combustion byproduct found in vehicle exhaust, cigarette smoke, smoke from burning wood, and grilled or charred food.
1-Methylphenanthrene
Breathed and eaten. Combustion byproduct found in vehicle exhaust, cigarette smoke, smoke from burning wood, and grilled or charred food.
1-Naphthylamine
Mostly occupational. Industrial chemical handled in manufacturing or research; the general public rarely encounters meaningful amounts.
1-Naphthylthiourea (ANTU)
Mostly occupational. Industrial chemical handled in manufacturing or research; the general public rarely encounters meaningful amounts.
1-Nitronaphthalene
Mostly occupational. Industrial chemical handled in manufacturing or research; the general public rarely encounters meaningful amounts.
1,2-Bis(chloromethoxy)ethane
Mostly occupational. Industrial chemical handled in manufacturing or research; the general public rarely encounters meaningful amounts.
1,2-Diamino-4-nitrobenzene
On skin. Ingredient in some permanent hair dyes; exposure for users and salon workers.
1,4-Bis(chloromethoxymethyl)benzene
Mostly occupational. Industrial chemical handled in manufacturing or research; the general public rarely encounters meaningful amounts.
1,4-Diamino-2-nitrobenzene
On skin. Ingredient in some permanent hair dyes; exposure for users and salon workers.
Reading IARC classifications carefully
The IARC groups describe the strength of evidence that an agent can cause cancer under some conditions — not the size of the risk to any individual, not the dose required, and not how likely exposure is in everyday life. A Group 1 classification does not mean an exposure is unavoidable or catastrophic; a Group 3 classification does not mean it is safe.