Registration Dossier

Administrative data

Description of key information

Vat Indigo Potassium Salt is only stable in aqueous alkaline solutions to prevent the Leuco-Lndigo from oxidising to Indigo  (pH >11.5). The registered substance oxidizes in the presence of water and air-borne oxygen within 5-15 minutes to Indigo (CAS-No. 482-89-3) and potassium hydroxide (100 g Produkt 1998 result in 33 g KOH). Due to the given corrosive effect of 30% KOH testing for acute toxicity of the alkaline solution is not possible. There is however sufficient data on indigo and leucoindigo showing that those substances are practically nontoxic any effects observed in preparations were due to the contained alkali fraction.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
4 430 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LC50
Value:
5 000 mg/m³

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
2 500 mg/kg bw

Additional information

The LD50 in several acute oral toxicity studies in rats with Indigo Küpe (Grains) was reported as > 2000, 4430, or > 5000 mg/kg body weight.

The LD50 in several acute oral toxicity studies in rats with indigo was reported as > 3160, > 5000, or > 6400 mg/kg body weight. These studies were non-GLP or GLP studies.

LC50 and LD50 values in acute inhalation and dermal toxicity studies with indigo in rats are > 5.3 mg/L/4 hrs and > 2500 mg/kg, respectively.

The LD50 for intraperitoneally administered indigo in mice was approximately 8000 mg/kg.

Justification for classification or non-classification

Test substance is practically non-toxic with different administration routes