- July 16, 2020
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
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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