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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Except a fish study which was performed in order to confirm the Read-Across approach between 1,4-bis(tert-butylperoxyisopropyl)benzene and 1,3-bis[1-(tert-butylperoxy)-1-methylethyl]benzene (see document attached to IUCLID), there is no data on 1,4-bis[1-(tert-butylperoxy)-1-methylethyl]benzene. Based on this read-across, one key study is available for each of the following endpoints:

Short term Toxicity to Fish:

The acute toxicity of 1,4-bis(tert-butylperoxyisopropyl)benzene to zebra fish has been investigated according to OECD 203 guideline in a GLP study. As no effect was observed during the preliminary test, a definitive limit-test at 100 mg/L was conducted and gave a 96-Hour LC50 of greater than 100% v/v saturated solution. The No Observed Effect Concentration was 100% v/v saturated solution. To conclude, this study showed no toxic effects at saturation.

Short term Toxicity to Aquatic invertebrates:

[1,3(or 1,4)-Phenylenebis(1-methylethylidene)]bis[tert-butyl]peroxide was not found to be acutely toxic to Daphnia magna when dispersed in water at a nominal loading rate of 1.0 mg/L equivalent to an initial mean measured concentration of 0.0219 mg/L. Consequently, the 48-hour EC50 value for [1,3(or 1,4)-Phenylenebis(1-methylethylidene)]bis[tert-butyl]peroxide could not be calculated but must be >1.0 mg/L (>0.0219 mg/L). The “no observed effect loading rate” was 1.0 mg/L (0.0219 mg/L as initial mean measured concentration).


Short term Toxicity to freshwater algae:

The acute toxicity of [1,3(or 1,4)-phenylenebis(1-methylethylidene)]bis[tert-butyl] peroxide was evaluated with Pseudokirschneriella subcapitata in a study performed in accordance with OECD testing guideline 201 and GLP requirements.

The algae were exposed to nominal test concentrations of 1 mg/L under static conditions during 72 hours. The mean measured concentrations were not maintained between 80 and 120 % of nominal. The test substance was not found to be acutely toxic to Pseudokirchneriella subcapitata at a nominal loading rate of 1.0 mg/L, equivalent to an initial mean measured concentration of 0.0471 mg/L.


Toxicity to microorganisms: in order to predict effects of chemicals in the environment and in biological wastewater treatment plants, an activated sludge respiration inhibition test was performed on 1,3-bis[1-(tert-butylperoxy)-1-methylethyl]benzene according to OECD 209 guideline and GLP requirements. The test substance was not soluble in water and therefore the activated sludge was exposed to bis (tert-butyl peroxy isopropyl)benzene adsorbed onto silica gel at a concentration of 1 g/L. By this exposure no effect was recorded indicating that the obtained distribution of 1,3-bis[1-(tert-butylperoxy) -1-methylethyl]benzene in the water system did not inhibit the activated sludge.


To summarize, no effect of 1,4-bis(tert-butylperoxyisopropyl)benzene was observed up to its water solubility limit.

According to claimed uses of 1,4-phenylenebis(1-methylethylidene)]bis[tert-butyl] peroxide aquatic compartment exposure is likely. At the moment no data is available for characterizing 1,4-phenylenebis(1-methylethylidene)]bis[tert-butyl] peroxide long-term effects on organisms inhabiting aquatic compartment. Risk assessment demonstrated that there is no risk for those organisms using the PNEC derived based upon acute data, however a long-term test on aquatic invertebrates was proposed with an analogous substance (CAS 25155-25-3). As soon as this test on CAS 25155-25-3 is available, the REACH dossier will be updated.