H334 — May cause allergy or asthma symptoms or breathing difficulties if inhaled
The GHS hazard statement for respiratory sensitization, category 1 (1a, 1b). Here is what it means, the label elements that travel with it, and the substances that carry it.
At a glance
| Official statement | May cause allergy or asthma symptoms or breathing difficulties if inhaled. |
| Hazard class | Respiratory sensitization |
| Category | Category 1 (1A, 1B) |
| Signal word | Danger |
| Pictogram |  GHS08 — Health hazard |
What it means
Can induce allergy or asthma-like hypersensitivity of the airways after it is inhaled. Sensitized workers can react to very low exposures.
Precautionary statements paired with H334
When the engine writes SDS Section 2 or a container label for a product carrying H334, these are the P-codes it assigns, in the official Annex 3 groups:
| Prevention | P261 | Avoid breathing dust/fume/gas/mist/vapors/spray. |
| P285 | In case of inadequate ventilation wear respiratory protection. | |
| Response | P304 | IF INHALED: |
| P311 | Call a POISON CENTER or doctor. | |
| P342 | If experiencing respiratory symptoms: | |
| Disposal | P501 | Dispose of contents/container in accordance with local/regional/national/international regulations. |
Substances that carry H334
189 of the 4,225 substances in our database carry H334 when classified in pure form — recognizable examples:
- glutaral — CAS 111-30-8
- (1S,3S,5R,6R)-(4-nitrophenylmethyl)-1-dioxo-6-phenylacetamido-penam-3-carboxylate — CAS 54275-93-3
- (1S,4R,6R,7R)-(4-nitrophenylmethyl)3-methylene-1-oxo-7-phenylacetamido-cepham-4-carboxylateido-penam-3-carboxylate — CAS 76109-32-5
- (1α,2α,3β,6β)-1,2,3,6-tetrahydro-3,6-methanophthalic anhydride — CAS 2746-19-2
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.