H331 — Toxic if inhaled
The GHS hazard statement for acute toxicity, inhalation, category 3. Here is what it means, the label elements that travel with it, and the substances that carry it.
At a glance
| Official statement | Toxic if inhaled. |
| Hazard class | Acute toxicity, inhalation |
| Category | Category 3 |
| Signal word | Danger |
| Pictogram |  GHS06 — Skull and crossbones |
What it means
Serious harm from breathing the substance — as gas, vapor, dust, or mist — over a single short exposure. Categories are set from acute toxicity estimates (ATE) per GHS Chapter 3.1.
Precautionary statements paired with H331
When the engine writes SDS Section 2 or a container label for a product carrying H331, these are the P-codes it assigns, in the official Annex 3 groups:
| Prevention | P261 | Avoid breathing dust/fume/gas/mist/vapors/spray. |
| P271 | Use only outdoors or in a well-ventilated area. | |
| Response | P304 | IF INHALED: |
| P311 | Call a POISON CENTER or doctor. | |
| P321 | Specific treatment (see supplemental first-aid instructions on this label). | |
| P340 | Remove person to fresh air and keep comfortable for breathing. | |
| Storage | P403 | Store in a well-ventilated place. |
| P405 | Store locked up. | |
| Disposal | P501 | Dispose of contents/container in accordance with local/regional/national/international regulations. |
Substances that carry H331
9 of the 4,225 substances in our database carry H331 when classified in pure form — recognizable examples:
- Methanol — CAS 67-56-1
- 2-Mercaptoethanol (BME) — CAS 60-24-2
- dicamba (ISO) — CAS 1918-00-9
- ethanethiol — CAS 75-08-1
The engine writes these for you.
When SDS HQ authors an SDS or a container label, it assigns the hazard statements, signal word, pictograms, and precautionary statements from these same tables — automatically, with the calculation shown.