Registration Dossier

Administrative data

Description of key information

LD50 oral = 1410 mg/kg bw

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
LD50
1 410 mg/kg bw

Additional information

The key study is a 1988 GLP guideline study of male and female rats exposed by oral gavage to toluene-4-sulphonic acid (CAS No, 104-15-4). The LD50 value was 1410 mg/kg bw. Given the predominance of deaths occurring within the day of exposure and the necropsy findings, it is likely that the deaths were a result of the acidity / corrosivity of the test substance. The internal examination findings (e.g., GI tract filled with blood; stomach haemorrhages and abdomen filled with fluid) suggest a secondary effect (i.e., corrosion) rather than a chemical toxicity.

In addition to the key study, there are 2 supporting acute oral studies a 1977 test of xylenesulphonic acid (CAS No. 25321-41-9) and a 1962 published study of benzenesulphonic acid (CAS No. 98-11-3). Both of these studies, as well as two additional published studies support the LD50 value of 1410 mg/kg bw reported in the key study.

There are not data for dermal acute toxicity. The aromatic sulphonic acids are corrosive and therefore with regard to animal welfare, dermal studies are not recommended. There are however acute dermal toxcity studies for the closely related hyrotropes that are the salt form of the sulphonic acids. The LD50 for the salts is >2000 mg/kg bw.

A single acute inhalation study concluded the acids are harmful at saturated air conditions as 3 of 6 animals died. A concentration was not reported.

Justification for classification or non-classification

Since it is not possible to directly assess the toxicity of sulphonic acids due to the corrosion/irritation effects, read-across from the hydrotopes resdults could be taken into account.

The studies with the salts (hydrotropes) provide valid read-across for the acids. The specific cation is not expected to have an appreciable effect on fate, ecotoxicity or mammalian toxicity and therefore the dataset for the entire hydrotropes category can be applied broadly. 

The aromatic sulphonic acids are almost completely ionized in watery environments even at low pH. The salts of these acids are the hydrotropes (or “sulphonates”) which include ammonium, calcium, potassium and sodium cations. In principle the salts get dissociated when in contact with water, so forming back to the acids. Because of their close chemical similarities and because much of the production of the aromatic sulphonic acids goes to manufacturing the salts, the extensive dataset for the hydrotropes can also be used as a source of read-across for endpoints in an aromatic sulphonic acid dossier. This is particularly relevant for studies that are conducted in water (e.g., ecotoxicity and biodegradation) as well as for mammalian toxicity studies where the relatively high acidity of the acid form has an immediate and harsh local effect, whereas the salt form provides an indication of potential systemic toxicity beyond the site of application or initial contac

No basis for acute toxicity classification is found.