Di-tert-butyl peroxide | Community rolling action plan (CoRAP) substance evaluation conclusions

The substance di-tert-butyl peroxide has a harmonised classification as Muta 2. However, new data were generated after the RAC opinion and the available mutagenicity summaries lacked details and were not conclusive for a decision on germ cell mutagenicity. Details on the studies were provided during the SEv process. In addition, new data became available for two related substances, including a comet assay study via inhalation performed with tert-butyl peroxide tert-butyl hydroperoxide (TBHP) and an in vitro micronucleus (MN) test with di-tert-butyl peroxide (dTPP), which both gave negative results. Also an in vitro study was performed to evaluate the reactive oxygen species (ROS) production of dTBP. The results confirmed the hypothesis that dTBP induced mutagenicity is related to ROS production, has a threshold mode of action and occurs only at high concentrations. The provided details of the available studies and the new data demonstrated that there is no concern for germ cell mutagenicity and that the substance is not considered Muta 1B.

The substance is classified as Muta 2, but no carcinogenicity data are available for the substance, which led to a concern on the carcinogenic potential of the substance. Assessment of the data showed that the substance is not irritating via dermal or inhalation exposure. The sub-chronic repeated dose toxicity study via inhalation shows no signs of pre-carcinogenic effects or local effects in the respiratory system. Available dermal tumor promotion studies are negative. Recently, a carcinogenicity study with TBHP became available as a result of a Compliance Check. The study demonstrated that carcinogenic effects are induced by TBHP, however, these effects were most likely initiated by irritation/corrosive injury to nasal tissues. These local effects were not induced by dTBP and therefore these carcinogenic effects are not expected for dTBP. It is concluded that there is no concern for carcionogenicity based on the current data and that no new data are needed.

For consumer uses, several process categories and product categories were described but no exposure scenarios or estimates were provided, which raised concerns. During the process, the dossier was updated and consumer uses and professional uses were removed. Therefore, the concern on consumer exposure is removed.

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