Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Rabbit: full thickness necrosis after 20 h occlusive exposure; superficial necrosis after 15 min occlusive exposure (standardized test protocol; BASF AG 1972)
Rabbit: corrosive effects after treatment with 0.05 mL (standardized test protocol; BASF AG 1972)
Respiratory system
no data available

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (corrosive)

Eye irritation

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

There are valid in vivo data available for the assessment of the skin and eye irritation potential of naphthalene-2 -sulfonic acid.



Shaved, intact skin of twoVienna White rabbits was exposed to presumably 1 g of 80% naphthalene-2-sulfonic acid in water for 20 h or 15, 5 or 1 min under occlusive conditions following a standardized test protocol (BASF AG 1972).The exposure of the test substance for 15 min to the skin of the back led to superficial necrosis and the exposure of the test substance for 20 hours to the skin led to full thickness destruction of the skin. Additionally, the pH of the test substance is < 2.0 (MSDS BASF, 1999). Therefore, the substance is classified as corrosive (causes burns, R34 according to EU-criteria and category 1C according to GHS-criteria).



A standardized eye irritation study was performed with two Vienna White rabbits (BASF AG 1972). Eyes were left unwashed after application of 0.05 mL naphthalene-2-sulfonic acid and were observed for 5 d.Necrosis of the margins of the eye lids and suppuration was observed at the end of the study, in addition marked corneal opacity was observed during the study. Due to this effects, iris and conjunctivae scores were not readable throughout the study. Naphthalene-2-sulfonic acid has therefore to be considered as corrosive also for the eye.


Respiratory system

No data available

Read across justification:

The registration item contains ca. 78.89% of naphthalene-2-sulphonic acid (CAS # 120-18-3) and ca. 6.5 % of naphthalene-1-sulphonic acid (CAS # 85-47-2). These two substances have the same molecular weight and are structurally almost identical. Therefore naphthalene-2-sulphonic acid and naphthalene-1-sulphonic acid and their respective salts are suitable for read across in order to fulfill the data requirements.

Effects on skin irritation/corrosion: corrosive

Effects on eye irritation: corrosive

Justification for classification or non-classification

Skin and Eye

Full thickness necrosis was observed in rabbits after 20 h of occlusive exposure to naphthalene-2-sulfonic acid. After 15 min exposure under similar conditions, superficial necrosis was observed. After treatment with 0.05 mL naphthalene-2-sulfonic acid, corrosive effects were also observed in rabbits eyes.

Regarding this, naphthalenesulfonic acids have to be considered as corrosive to skin and eyes (R34 according to EU criteria and Cat. 1C according to UN-GHS criteria, respectively).