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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Leuco Sulfur Black 1 did not cause any toxic effects in the repeated dose toxicity study with reproduction/developmental toxicity screening in rats (OECD 422). The limit dose of 1000 mg/kg bw/d represents the NOAEL.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Dose descriptor:
1 000 mg/kg bw/day
Study duration:

Additional information

In a repeated dose toxicity study according to OECD guideline 422 and GLP Leuco Sulfur Black 1 was administered by gavage to groups of 10 rats per sex and dose at 0, 100, 300 and 1000 mg/kg bw/d. Male rats were treated for 29 days, female rats for 14 days prior to pairing, though the pairing and gestation periods until the F1 generation had reached day 4 post partum. The test item was administered in water as vehicle at a dose volume of 10 mL/kg bw/d. Control animals were doses with the vehicle alone.

Observation and examinations consisted of mortality, clinical signs, detailed clinical observations, food consumption, body weight, functional observation battery, clinical biochemistry, haematology, urinalysis, macroscopical examination at necropsy, organ weights and histopathological examination of organs. The only effect seen was a dark discolouration of faeces in all high dose animals starting on day 3 of the study and lasting until termination. Based on this finding a NOAEL of 1000 mg/kg bw/d was derived.

The discolouration of faeces was the only effect observed in this study and also in the acute oral toxicity study. Organs or urine were not discoloured and signs of substance deposits were not found in histopathological analysis of the organs. This indicates that Leuco Sulfur Black 1 is directly excreted and that absorption in the gastrointestinal tract does not occur following oral administration.

The mean molecular weight and number-average molecular weight (Mn) of Leuco Sulfur Black 1 > 8000 Da. It is very poorly or even not soluble in common polar and non-polar solvents such as water (solubility of 62.4 mg/L), DMSO, methanol, DMF, THF, chloroform and not soluble in acid likes sulfuric acid and trifluoroacetic acid. The vapour pressure of the pure substance, calculated from the boiling point of > 400 °C, is 1.8 x 10E-5 hPa at 25 °C. These substance properties supported by the results of oral toxicity studies demonstrate that the absorption of Leuco Sulfur Black 1 via the oral, dermal or inhalation route is negligible and, consequently, that systemic bioavailability is also negligible. Based on the substance properties and the fact that no toxicity was seen in any of the available toxicity studies it is concluded that exposure to Leuco Sulfur Black 1 does not raise any health concern. In line with Regulation (EC) No 1907/2006 Annex XI and taking into account the REACH paradigm that new tests on vertebrates shall only be conducted or proposed as a last resort when all other data sources have been exhausted, further animals studies to examine the repeated dose toxicity of Leuco Sulfur Black 1 are not necessary and should not be performed.

Justification for classification or non-classification

Based on the available data Leuco Sulfur Black 1 is not subject to classification and labelling according to Directive 67/548/EECand Regulation 1272/2008/EC.