Registration Dossier

Administrative data

Key value for chemical safety assessment

Additional information

In vitro gene mutation study in bacteria (Ames test):

In the key study (Gridley & Ross 1980) Salmonella typhimurium strains TA1535, TA1537, TA98 and TA100 were treated with suspensions of the test material using the Ames plate incoporation method and conducted at concentrations of ≤ 10 mg of sample per plate both with and without the addition of a rat microsomal activation system. No mutagenic activity was observed,

In vitro cytogenicity study in mammalian cells (chromosome aberration test):

In the key study (Stewart 1981) the effect of monosodium cyanurate on sister chromatid exchange (SCE) frequencies in cultured Chinese hamster ovary (CHO) cells was evaluated. Without metabolic activation CHO cells were exposed to five concentrations ranging from 93.8 to 1500 µg/mL. With metabolic activation, CHO cells were exposed to five concentrations ranging from 93.6 to 1500 µg/mL. Monosodium cyanurate did not induce SCEs in CHO cells with or without metbolic activation.

In vitro gene mutation study in mammalian cells (mouse lymphoma assay):

In the key study (Kirby 1981) cyanuric acid (sodium salt) was tested in the L5178Y TK +/- Mouse Lymphoma Mutagenesis Assay with and without metabolic activation by induced rat liver S-9. The cultures treated without activation were cloned over a range of concentrations which produced from 69% to 113% suspension growth, and the cultures receiving S-9 metabolic activation were cloned over a range of concentrations which produced from 94% to 105% suspension growth. The results showed that the test material did not cause a significant increase in mutant frequency.

In vivo gene mutation:

In the key study (Sharma 1982)the mutagenic potential of sodium cyanurate was evaluated using the in vivo rat bone marrow cytogenetics assay. The test material was administered to male rats by gavage. In each treatment group five animals each were dosed with 0, 1.25, 2.5 and 5.0 g/kg sodium cyanurate.Chromosomal preparations were made from bone marrow cells following 24 and 48 hours exposure.

The frequency of aberrations per cells was compared with that of the negative control (4% carboxymethyl cellulose). None of the doses tested produced means that were significantly different from the negative control.


Short description of key information:
The chlorinated isocyanurates are unstable in the body, particularly the stomach, because the free available chlorine is rapidly reduced. CYA, or its salt, is the stable degradation product. Therefore, CYA, or its sodium salt, is the substance of interest for the genotoxicity toxicity studies. Three in vitro toxicity studies are available with CYA (Ames, chromosome aberration and mouse lymphoma assay) and an in vivo rat chromosome aberration study. There was no evidence of genotoxicity in either of the studies.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

The chlorinated isocyanurates are unstable in the body, particularly the stomach, because the free available chlorine is rapidly reduced. CYA, or its salt, is the stable degradation product. Therefore, CYA, or its sodium salt, is the substance of interest for the genotoxicity toxicity studies.There is no evidence of genotoxic potential of CYA in in-vitro studies with and without metabolic activation and in an in-vivo rat chromosome aberration study. Classification is therefore not warranted.