GHS Health Hazard Symbol: What It Means and When It Applies
The GHS health hazard symbol — officially designated GHS08 — is one of the most important pictograms in the GHS system, yet it is frequently misunderstood. Unlike the skull and crossbones (GHS06), which signals immediate acute danger, GHS08 warns about serious long-term health effects that may not be immediately obvious.
What Does the GHS Health Hazard Symbol Look Like?
GHS08 shows a human silhouette with a starburst pattern emanating from the chest area, enclosed in a red diamond border on a white background. The starburst represents internal organ damage or systemic health effects.
It is distinct from:
- GHS06 (skull and crossbones) — acute, immediate toxicity
- GHS07 (exclamation mark) — mild to moderate irritation effects
A substance can carry both GHS08 and GHS06 simultaneously if it is both acutely toxic and a long-term health hazard.
Which Hazard Classes Trigger GHS08?
GHS08 is assigned when a substance is classified in any of the following hazard classes:
1. Respiratory Sensitisation (Category 1)
A respiratory sensitiser is a substance that causes hypersensitivity of the airways after inhalation. Once sensitised, a person may react to even trace amounts of the substance.
Relevant H-statement:
- H334 — May cause allergy or asthma symptoms or breathing difficulties if inhaled
Common respiratory sensitisers include isocyanates (used in polyurethane production), certain metal compounds (platinum salts, chromates), and some flour proteins.
2. Germ Cell Mutagenicity
Mutagens alter the genetic information in cells. Germ cell mutagens specifically affect reproductive cells (sperm and eggs), meaning mutations can be passed to future generations.
Relevant H-statements:
- H340 — May cause genetic defects (Categories 1A and 1B)
- H341 — Suspected of causing genetic defects (Category 2)
Category 1A substances have demonstrated mutagenicity in humans. Category 1B is based on strong animal evidence. Category 2 is based on limited evidence and uses “suspected of.”
3. Carcinogenicity
Carcinogens are substances that can cause cancer or increase cancer incidence.
Relevant H-statements:
- H350 — May cause cancer (Categories 1A and 1B)
- H351 — Suspected of causing cancer (Category 2)
Examples of well-known carcinogens with GHS08:
| Substance | CAS | Category | Route |
|---|---|---|---|
| Benzene | 71-43-2 | 1A | Inhalation/Skin |
| Formaldehyde | 50-00-0 | 1B | Inhalation |
| Benzo[a]pyrene | 50-32-8 | 1B | Multiple |
| Styrene | 100-42-5 | 2 | Inhalation |
| Acrylamide | 79-06-1 | 1B | Multiple |
| Ethylene oxide | 75-21-8 | 1A | Inhalation |
Category 1A carcinogens have known human evidence (typically from epidemiological studies). Category 1B is based on animal studies with strong relevance to humans.
4. Reproductive Toxicity
Reproductive toxins affect sexual function, fertility, or development of offspring (including effects via lactation).
Relevant H-statements:
- H360 — May damage fertility or the unborn child (Categories 1A and 1B)
- H361 — Suspected of damaging fertility or the unborn child (Category 2)
- H362 — May cause harm to breast-fed children (Lactation category)
Note: H362 does not trigger GHS08 but is listed as a supplementary hazard statement on labels.
Examples of reproductive toxins:
| Substance | CAS | Effect |
|---|---|---|
| Lead and lead compounds | 7439-92-1 | Developmental, fertility |
| Mercury compounds | 7439-97-6 | Developmental |
| Boric acid | 10043-35-3 | Reproductive (Cat 1B) |
| N,N-Dimethylformamide | 68-12-2 | Developmental (Cat 1B) |
| Valproic acid | 99-66-1 | Developmental |
5. Specific Target Organ Toxicity — Single Exposure (STOT SE)
STOT SE covers substances that cause specific, non-lethal target organ toxicity after a single exposure. This affects organs such as the liver, kidneys, nervous system, or blood.
Relevant H-statements:
- H370 — Causes damage to organs (Category 1) — signal word: DANGER
- H371 — May cause damage to organs (Category 2) — signal word: WARNING
STOT SE Category 3 (H335, H336) does not trigger GHS08 — it uses the milder GHS07 instead.
Examples:
- Carbon tetrachloride — liver damage (STOT SE Cat 1)
- n-Hexane — central nervous system (STOT SE Cat 1)
- Dichloromethane — CNS, carboxyhemoglobin effects (STOT SE Cat 3 — GHS07 only)
6. Specific Target Organ Toxicity — Repeated Exposure (STOT RE)
STOT RE covers damage caused by prolonged or repeated exposure over time — the classic occupational health scenario.
Relevant H-statements:
- H372 — Causes damage to organs through prolonged or repeated exposure (Category 1) — signal word: DANGER
- H373 — May cause damage to organs through prolonged or repeated exposure (Category 2) — signal word: WARNING
Examples:
- Silica (crystalline) — H372 — lung damage (silicosis), STOT RE Cat 1
- Toluene — H373 — central nervous system, STOT RE Cat 2
- n-Hexane — H372 — peripheral nervous system
7. Aspiration Hazard
Aspiration means entry of liquid or solid into the trachea and lower respiratory tract during swallowing or vomiting. Aspiration of certain liquids — particularly hydrocarbon solvents — can cause severe chemical pneumonia and is potentially fatal.
Relevant H-statement:
- H304 — May be fatal if swallowed and enters airways (Category 1)
Substances with low dynamic viscosity (< 20.5 mm²/s at 40°C) and low surface tension are at particular risk. Petroleum distillates, lighter fluid, and many hydrocarbon-based products carry H304.
Examples:
- Naphtha (petroleum) — H304
- Turpentine — H304
- Kerosene — H304
- Many alkane mixtures — H304
Signal Words for GHS08
Unlike some other pictograms that always use the same signal word, GHS08 can carry either DANGER or WARNING depending on the specific classification:
- DANGER: H334, H340, H350, H360, H370, H372
- WARNING: H341, H351, H361, H371, H373
If a substance has both DANGER and WARNING classifications, only DANGER appears on the label.
GHS08 and SVHC Status under REACH
Many substances with GHS08 are also classified as Substances of Very High Concern (SVHC) under REACH Regulation (EC) No 1907/2006. SVHCs include:
- Substances meeting criteria for CMR (carcinogenic, mutagenic, reprotoxic) Category 1A or 1B
- Persistent, bioaccumulative and toxic (PBT) substances
- Very persistent and very bioaccumulative (vPvB) substances
SVHCs placed on the REACH Candidate List trigger mandatory communication obligations: suppliers of articles containing > 0.1% w/w of an SVHC must notify customers and the general public upon request.
How to Identify Chemicals with GHS08
Our Hazards Database contains 4,178 substances with complete GHS classifications. You can search by:
- Chemical name (IUPAC or common name)
- CAS number — the universal chemical identifier
- EC number — for EU-registered substances
Each substance page shows all applicable pictograms including GHS08, along with the specific H-statements, signal word, P-statements, and ATE values where available.
Search chemicals with GHS08 Health Hazard →
Working Safely with GHS08 Substances
When handling substances bearing the health hazard symbol:
- Read the SDS thoroughly — Section 8 (Exposure controls) and Section 11 (Toxicological information) are critical
- Implement engineering controls first — local exhaust ventilation, closed systems
- Use appropriate PPE — type depends on H-statements (respiratory protection for H334, H340; chemical-resistant gloves for skin-absorbed carcinogens)
- Monitor exposure — biological monitoring or air sampling for STOT RE substances
- Observe occupational exposure limits — OELs exist for most common STOT RE Cat 1 substances
For EHS managers, maintaining a register of all GHS08 substances on site — particularly CMR substances — is a requirement under the EU Chemical Agents Directive and national legislation.
Related Resources
- GHS Hazard Symbols and Meanings — all 9 GHS pictograms overview
- GHS H-Statements Complete Guide — H340, H350, H360, H372 and related codes
- GHS Signal Words: Danger vs Warning — GHS08 always triggers Danger
- GHS vs OSHA HCS 2024 — updated CMR classification requirements
Reference: UN GHS Rev.9, Chapters 3.4–3.10. CLP Regulation (EC) No 1272/2008, Annex I, Part 3. REACH Regulation (EC) No 1907/2006, Article 57.