What is IARC Group 2A?
Group 2A — probably carcinogenic. 25 factors in the Meyron reference are currently classified this way.
Plain-language explanation
Likely to cause cancer. Evidence in humans is limited, but strong in animals or other studies.
Examples
Glyphosate
On skin and breathed. The active ingredient in many commercial and consumer weedkillers. Highest exposure is agricultural; home gardeners and landscapers also use it.
High-temperature cooked meat (HCAs and PAHs)
Eaten. Compounds that form when meat (beef, pork, chicken, fish) is cooked at very high temperatures — especially grilled over open flame, pan-fried until well-done, or barbecued.
Night shift work
Lifestyle. Regular work shifts during the biological night that disrupt circadian rhythms — common in healthcare, transport, security, and manufacturing.
Red meat
Eaten. Unprocessed beef, pork, lamb, and similar mammalian muscle meat.
Very hot beverages (above 65 °C)
Drunk. Tea, coffee, soup, mate, or other beverages consumed above 65 °C (149 °F). The temperature is what matters, not the drink — letting it cool eliminates this risk.
Acrylamide
Eaten. Forms during high-temperature cooking of starchy foods — fried potatoes, crisps, toast, biscuits, and coffee roasting. Reducing browning reduces exposure.
Hydrochlorothiazide
Prescription medication. A common diuretic ("water pill") used to treat high blood pressure.
Indoor biomass fuel smoke (wood)
Breathed. Cooking or heating with wood, charcoal, dung, or crop residues — especially on open fires or unvented stoves. Roughly a third of the world cooks this way.
Tetrachloroethylene (perchloroethylene)
Breathed. Solvent used in dry cleaning. Dry-cleaning workers and people living near dry-cleaning facilities can be exposed.
2-Mercaptobenzothiazole
Mostly occupational. Industrial chemical handled in manufacturing or research; the general public rarely encounters meaningful amounts.
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.