Chlorobenzene

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Chlorobenzene was tested for its potential of being a skin sensitizer in the GPMT according to Magnusson and Kligman (Mihail, 1984). On the basis of preliminary dose-finding results, the experiment was carried out using the test substance at the following concentrations: Intradermal Induction: 1% ; Topical induction: 50% ; 1st Challenge: 25% ; 2nd Challenge: 25%. Both challenges showed no significant differences between treated and control animals. According to the findings, chlorobenzene is not considered to be a sensitizer.However, the test is considered of limited reliability because of several reasons. The major ones are that on the one hand the control group showed positive results as well and on the other hand no positive control or reliability check was reported. Nevertheless, the German BUA report of chlorobenzene (No. 54, 1990) states, that this study gives no indication of a sensitizing effect.

This conclusion is supported by a publication of Ashby (1995)

In the publication local lymph node data for 106 chemicals (chlorobenzene among them) are listed, broad structure activity relationships (SAR) were suggested, and 8 classes of agent were discerned In addition, test conditions (Analytical purity not reported. Housing condition not reported. Positive control or reliability check not reported. Method not reported in detail). Therefore the reliability is considered limited.

Chlorobenzene was tested in the murine local lymph node assay (LLNA) with a method similar to OECD TG 429 with deviations Groups of mice were exposed daily, for 3 consecutive days, to 5, 10, and 25% of chlorobenzene or to the vehicle alone, on the dorsum of both ears. Subsequently (conventionally 5 days following the initiation of the exposure), mice were injected intravenously with [3H]-thymidine and activity measured as a function of isotope incorporation in draining auricular lymph nodes.

Stimulation indices after exposure to 5, 10, and 25% of chlorobenzene, were respectively 1.1, 1.7, and 1.6.

Chlorobenzene was reported to be inactive in the lymph node assay (LLNA) and therefore not sensitising.

Migrated from Short description of key information:
Chlorobenzene was tested for its potential of being a skin sensitizers in a limited Guinea Pig Maximization test according to Magnusson and Kligman (Mihail, F (1984). According to the findings in this test chlorobenzene is not considered to be a sensitizer. Furthermore, in the publication Ashby, J. et al., Toxicology 103, 177-194 (1995) local lymph node data for 106 chemicals (chlorobenzene among them) are listed. Chlorobenzene is reported to be inactive in the murine local lymph node assay (LLNA) and therefore considered not to be a skin sensitizer

Justification for classification or non-classification

According to Annex VI of the Regulation 1272/2008 EC chlorobenzene is not classified. Based on the available data no classification is proposed.