Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Description of key information

acute toxicity

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
5 000 mg/kg bw
Quality of whole database:
oral, rats

Acute toxicity: via inhalation route

Endpoint conclusion
Dose descriptor:
11 800 mg/m³ air
Quality of whole database:
inhalation, rats, 4-hour

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

The experimental data on acute toxicity of styrene include studies by inhalation and oral exposure performed in rodents. The data on oral exposure to styrene are, generally, well above the threshold for classification of styrene for acute toxicity (i.e. > 2000 mg/kg bw). However, the data on acute toxicity in rats via inhalation exposure route (10 mg/L <LC50 ≤ 20 mg/L) suggest moderate acute toxicity of styrene.

Styrene has harmonized at EU level classifications and it is classified as Xn; R20 – Harmful by inhalation, in accordance with Directive 67/548/EEC, and Acute Toxicity, Hazard Category 4, H332: Harmful if inhalled, in accordance with the GHS criteria of Regulation (EC) No 1272/2008.


In general, high concentrations of styrene were reported to result in dizziness, drowsiness, headache, nausea, vomiting, weakness, and unconsciousness.


Given, that styrene is used in industry for a long time, the lack of reports on serious adverse acute toxicity effects (e.g., death) of styrene support the low acute toxicity of styrene.


Styrene is a hydrocarbon with reported dynamic viscosity of 0.7 cP at 25°C. This value would correspond to a kinematic viscosity of approx. 0.8 mm2/s at 25°C, which is less than a GHS/CLP threshold value of 20.5 mm2/s (at 40°C) for classification of substances for aspiration toxicity.


Styrene is, therefore, self- classified as Aspiration Toxicity Category 1 substance, H304: May be fatal if swallowed and enters airways.

In conclusion, it considered that styrene is of moderate acute toxicity in experimental animals by inhalation.

Justification for classification or non-classification