GHS / HazCom term · Glossary
Carcinogenicity
Verified vs OSHA sources · 2026-10-05
A GHS health-hazard class for chemicals that cause cancer or increase its incidence. GHS (and OSHA's HazCom standard) sorts carcinogens into Category 1A (known human carcinogen), 1B (presumed, from animal evidence), and Category 2 (suspected). Carcinogens carry the health-hazard pictogram (GHS08) and a hazard statement such as H350 (“May cause cancer”).
Also known as: carcinogen classification
Carcinogenicity at a glance
- Three GHS categories: 1A (known), 1B (presumed), 2 (suspected).
- Pictogram is GHS08 (health hazard); signal word is “Danger” for 1A/1B, “Warning” for 2.
- Hazard statements: H350 “May cause cancer” (1A/1B); H351 “Suspected of causing cancer” (2).
- Separate from IARC and NTP classifications, which are evidence reviews that inform — but aren't — the GHS label class.
In plain English
How a chemical label tells you something can cause cancer. GHS ranks the evidence: 1A means it's known to cause cancer in people, 1B means it's presumed to (mostly from animal studies), and 2 means it's suspected. All three get the health-hazard symbol (the starburst-chest figure).
What the rule says
“Carcinogenicity refers to the induction of cancer or an increase in the incidence of cancer occurring after exposure to a substance or mixture.”
In context
A classification or labeling concept from the UN Globally Harmonized System, adopted into US law through OSHA's Hazard Communication Standard (29 CFR 1910.1200) and its appendices.
Where this is written in OSHA's rules
- 29 CFR 1910.1200 App A.6Read on eCFR / OSHA.gov
Example
Benzene is classified as a Category 1A carcinogen — known to cause cancer (leukemia) in humans — so its label carries the health-hazard pictogram (GHS08), the signal word “Danger,” and the hazard statement H350, “May cause cancer.” OSHA also regulates benzene under its own substance-specific standard (1910.1028).
Why it matters
A carcinogen classification drives stricter labeling, training, and often a substance-specific OSHA standard (benzene, formaldehyde, the 13 OSHA-regulated carcinogens). Mislabeling a known carcinogen — wrong category, missing GHS08, or no cancer hazard statement — understates a serious long-latency risk and is a HazCom violation.
GHS category vs. IARC / NTP classification
GHS Categories 1A/1B/2 are what appear on the label under OSHA's HazCom rule. IARC (Groups 1, 2A, 2B, 3) and the US NTP (“known” / “reasonably anticipated”) are separate scientific bodies that evaluate cancer evidence. Their findings inform a GHS classification but use different names and aren't themselves the label class.
GHS carcinogenicity categories
| Category | Meaning | Evidence basis | Signal word |
|---|---|---|---|
| 1A | Known human carcinogen | Human evidence | Danger |
| 1B | Presumed human carcinogen | Animal evidence | Danger |
| 2 | Suspected human carcinogen | Limited evidence | Warning |
Carcinogenicity: frequently asked questions
- What are the GHS carcinogenicity categories?
- Category 1A (known human carcinogen, based on human evidence), Category 1B (presumed, based on animal evidence), and Category 2 (suspected, based on limited evidence). 1A and 1B use the signal word “Danger” and H350; Category 2 uses “Warning” and H351.
- Is the GHS carcinogen category the same as the IARC group?
- No. GHS Categories 1A/1B/2 are the hazard-communication label classes under OSHA's standard. IARC Groups (1, 2A, 2B, 3) and NTP listings are separate scientific evaluations of cancer evidence; they inform classification but aren't the GHS label category.
- What pictogram is used for carcinogens?
- The health-hazard pictogram, GHS08 (a human silhouette with a starburst on the chest). It also covers mutagenicity, reproductive toxicity, respiratory sensitization, STOT, and aspiration hazards.
Related terms
Free tools for this
Governing OSHA standards
More GHS terms
A GHS health-hazard class for the harmful effects that follow a single dose, several doses within 24 hours, or a 4-hour inhalation exposure. Chemicals are sorted into categories by route (oral, dermal, inhalation) using LD50/LC50 cut-offs — Category 1 is the most toxic. OSHA's HazCom standard uses Categories 1–4.
Aspiration HazardA GHS health-hazard class for chemicals that can be fatal if swallowed and then enter the airways — directly or by vomiting — causing chemical pneumonia or lung injury. Thin, low-viscosity hydrocarbons (gasoline, kerosene, lamp oil) are the classic example. It is Category 1, with the health-hazard pictogram (GHS08) and signal word “Danger.”
Chemicals Under PressureA physical-hazard class added by OSHA's 2024 HCS update (aligning with GHS Revision 7) for liquids or solids pressurized with a gas, held in pressure receptacles other than aerosol dispensers and not classified as gases under pressure. It is categorized by the flammability of its contents and always carries the gas-cylinder pictogram (GHS04) for the pressure hazard.
ClassificationThe process of evaluating the available scientific evidence for a chemical against the GHS criteria to decide whether it is hazardous and, if so, the hazard class and category of each effect. Classification is the first step in HazCom — its result determines every label element (pictogram, signal word, hazard and precautionary statements) and SDS content.
Corrosive to MetalsA GHS physical-hazard class for chemicals that, by chemical action, will materially damage or even destroy metals. It is a single category (Category 1), determined by corrosion-rate testing on steel and aluminum, and uses the corrosion pictogram (GHS05) with the hazard statement H290. It is a separate hazard from skin corrosion, even though both use GHS05.
Desensitized ExplosivesA physical-hazard class added by OSHA's 2024 HCS update (GHS Revision 7) for solid or liquid explosives that have been phlegmatized — wetted or diluted — to suppress their explosive properties for safe transport and storage. It has four categories based on the corrected burning rate, and uses the flame pictogram (GHS02), not the exploding-bomb.
Globally Harmonized System (GHS)An internationally agreed framework created by the United Nations (first adopted in 2003) that standardizes how chemical hazards are classified and communicated — using common hazard classes, pictograms, signal words (Danger / Warning), and coded hazard (H) and precautionary (P) statements on labels and safety data sheets. The US adopted GHS into law through OSHA's 2012 Hazard Communication Standard update.
GHS Revision 7The 7th revision of the UN Globally Harmonized System, which OSHA adopted in its 2024 update to the Hazard Communication Standard (with selected elements of Revision 8). It adds new hazard classes — desensitized explosives and chemicals under pressure — folds pyrophoric and chemically unstable gases into flammable gases, and updates label and SDS provisions. The final rule was effective July 19, 2024, with phased compliance dates.
Sources & verification
- 29 CFR 1910.1200 App A.6 (eCFR / OSHA.gov)
- OSHA — Appendix A to §1910.1200: Health Hazard Criteria (Mandatory)
- NIOSH — Occupational Cancer / Carcinogen classification
Reviewed by HazComFast against eCFR, OSHA.gov, NIOSH, and the Federal Register. Last reviewed 2026-10-05. This glossary is general information, not legal advice; OSHA State-Plan states (e.g. California, Michigan) may adopt stricter requirements.
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