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Key value for chemical safety assessment

Additional information

The substance was non-mutagenic in a bacterial reverse mutation assay according to OECD TG 471 with 5 Salmonella typhimurium-strains (TA 1535, TA 100, TA 1537, TA 98, TA 102).

For assessment of further endpoints of genetic toxicity a read across to HDI oligomers, isocyanurate type (EC 931 -274 -8) is applied. This substance is a close structural analogue to HDI oligomers, iminooxadiazindione type, also derived from catalytic oligomerisation of 1,6 -hexamethylene diisocyanate (HDI; CAS 822 -06 -0) and also belonging to the CAS number 28182-81-2 (Hexane, 1,6 - diisocyanato-, homopolymer). The read across is based on physicochemical and toxicological similarity. In fact, comparison of the toxicological endpoints, that are available for both of the two substances reveal good correlation.

 Toxicological endpoint  HDI oligomers, isocyanurate type  HDI oligomers, iminooxadiazindione type
 Acute oral toxicity  > 2000 mg/kg  > 2000 mg/kg
 Acute inhalation toxicity (pulmonary irritant study) NOAEL 3 mg/m³   NOAEL 2.1 mg/m³
 Skin Irritation/Corrosion  slight irritation/no classification required  slight irritation/no classification required
 Eye Irritation/Corrosion  very slight irritation/no classification required  very slight irritation/no classification required
 Skin Sensitisation  classification required  classification required
 Bacterial Mutagenicity (Ames)  negative  negative

With respect to Inhalation Toxicity an expert statement is available justifying the read across (Pauluhn, Comparison of pulmonary irritation potency..., Bayer HealthCare AG, 2008).

Therefore, test results obtained for HDI oligomers, isocyanurate type can be transferred to HDI oligomers, iminooxadiazindione type and the data of genetic toxicity for HDI oligomers, isocyanurate type are also valid for HDI oligomers, iminooxadiazindione type. This approach is in accordance with Annex XI, section 1.5 of the REACH Regulation (Regulation (EC) No 1907/2006).

Read across to the HDI oligomers, isocyanurate type gave no evidence of mammalian cell mutagenicity (report no. 50M0355/064102, 2007, HPRT; report no. 1053/027, 2004, mouse lymphoma assay; both OECD TG 476) or of in vitro/in vivo chromosome aberration (report no. 32M0355/064051, 2007, CAb/OECD TG 473; report no. 4110, 1986, MNT/OECD TG 474). Therefore it was concluded that HDI oligomers, iminooxadiazindione type is no genetic toxicant.

Justification for selection of genetic toxicity endpoint
None of the available studies is selected since all are relevant for the assessment of genetic toxicity.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

According to Regulation (EC) No 1272/2008, Annex I, no classification is warranted for genetic toxicity.