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Annex II Entry 1553 CMR30/07/2020

Di-tert-butyl peroxide

Di-tert-butyl peroxide is listed in Annex II as a prohibited substance for cosmetic products placed on the EU market.

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Prohibited substance— Annex II, EU Regulation 1223/2009
Entry: 1553
CMR

Chemical identity and properties

PubChem 2D chemical structure for CAS 110-05-4
CAS 110-05-4PubChem CID 8033

Di-tert-butyl peroxide

Di-tert-butyl peroxide is a clear colorless liquid. (NTP, 1992) — CAMEO Chemicals

IUPAC name
2-tert-butylperoxy-2-methylpropane
Molecular formula
C8H18O2
Molecular weight
146.23 g/mol
Exact mass
146.130679813 Da
XLogP3
2.1
Topological polar surface area
18.5 Ų
Hydrogen-bond donors
0
Hydrogen-bond acceptors
2
Covalent units
1
Defined stereocentres
0

Also known as

tert-Butyl peroxidet-Butyl peroxideDTBPTrigonox BCadox TBPCadoxKayabutyl DPerbutyl D
16 more reported names
Interox DTBtert-ButylperoxidePeroxide, bis(1,1-dimethylethyl)Bis(tert-butyl) peroxideDi-tert-butylperoxidDi-tert-butyl peroxydePeroxyde de butyle tertiaireBis(t-butyl)peroxideDi-tert-Butyl hydroperoxidePerossido di butile terziarioBis(1,1-dimethylethyl) peroxidedi-t butyl peroxideBIS(1,1-DIMETHYLETHYL)PEROXIDEM7ZJ88F4R1NSC-673TBHP compound
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

Evidence from additional scientific databases

NIH PubChem PUG-View
Exact identifier match8033

Attributed physical-property, hazard, environmental and use annotations.

  • First Aid: EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.; SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment.; INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) shou Source: CAMEO Chemicals
  • Signal: Danger Source: Regulation (EC) No 1272/2008 of the European Parliament and of the Council
  • GHS Hazard Statements: H225: Highly Flammable liquid and vapor [Danger Flammable liquids]; H242: Heating may cause a fire [Danger Self-reactive substances and mixtures; Organic peroxides]; H341: Suspected of causing genetic defects [Warning Germ cell mutagenicity] Source: Regulation (EC) No 1272/2008 of the European Parliament and of the Council
  • Precautionary Statement Codes: P203, P210, P233, P234, P235, P240, P241, P242, P243, P280, P303+P361+P353, P318, P370+P378, P403, P403+P235, P405, P410, P411, P420, and P501 (click each P-code to see the statement) Source: Regulation (EC) No 1272/2008 of the European Parliament and of the Council
  • Signal: Danger Source: European Chemicals Agency (ECHA)
  • GHS Hazard Statements: H225 (> 99.9%): Highly Flammable liquid and vapor [Danger Flammable liquids]; H242 (> 99.9%): Heating may cause a fire [Danger Self-reactive substances and mixtures; Organic peroxides]; H319 (35.6%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]; H334 (14.1%): May cause allergy or asthma symptoms or breathing difficulties if inhaled [Danger Sensitization, respiratory]; H341 (62.5%): Suspected of causing genetic defects [Warning Germ cell mutagenicity]; H412 (11.3%): Harmful to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard] Source: European Chemicals Agency (ECHA)
  • Precautionary Statement Codes: P203, P210, P233, P234, P235, P240, P241, P242, P243, P260, P264+P265, P271, P273, P280, P284, P303+P361+P353, P304+P340, P305+P351+P338, P318, P337+P317, P342+P316, P370+P378, P403, P403+P235, P405, P410, P411, P420, and P501 (click each P-code to see the statement) Source: European Chemicals Agency (ECHA)
  • ECHA C&L Notifications Summary: Aggregated GHS information provided per 1252 reports by companies from 14 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.; Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website. Source: European Chemicals Agency (ECHA)
  • Signal: Danger Source: NITE-CMC
  • GHS Hazard Statements: H225: Highly Flammable liquid and vapor [Danger Flammable liquids]; H242: Heating may cause a fire [Danger Self-reactive substances and mixtures; Organic peroxides]; H341: Suspected of causing genetic defects [Warning Germ cell mutagenicity]; H402: Harmful to aquatic life [Hazardous to the aquatic environment, acute hazard] Source: NITE-CMC
  • Precautionary Statement Codes: P203, P210, P233, P234, P235, P240, P241, P242, P243, P273, P280, P303+P361+P353, P318, P370+P378, P403, P403+P235, P405, P410, P411, P420, and P501 (click each P-code to see the statement) Source: NITE-CMC
  • Signal: Warning Source: NITE-CMC
  • GHS Hazard Statements: H341: Suspected of causing genetic defects [Warning Germ cell mutagenicity] Source: NITE-CMC
  • NFPA Health Rating: 3 - Materials that, under emergency conditions, can cause serious or permanent injury. Source: Hazardous Substances Data Bank (HSDB)
  • NFPA Fire Rating: 2 - Materials that must be moderately heated or exposed to relatively high ambient temperatures before ignition can occur. Materials would not under normal conditions form hazardous atmospheres with air, but under high ambient temperatures or under moderate heating could release vapor in sufficient quantities to produce hazardous atmospheres with air. Source: Hazardous Substances Data Bank (HSDB)
  • NFPA Instability Rating: 4 - Materials that in themselves are readily capable of detonation or explosive decomposition or explosive reaction at normal temperatures and pressures. Source: Hazardous Substances Data Bank (HSDB)
  • NFPA Specific Notice: OX - Oxidizer: Materials that possess oxidizing properties. Source: Hazardous Substances Data Bank (HSDB)
  • Toxicity Summary: IDENTIFICATION AND USE: Bis(1,1-dimethylethyl) peroxide is a liquid. It is used as a polymerization catalyst for resins, including olefins, styrene, styrenated alkyds, and silicones. It is also used as an ignition accelerator for diesel fuel, and an organic synthesis intermediate. HUMAN STUDIES: Workers engaged in the production of organic peroxides suffered from grippe, angina, acute respiratory diseases, and pneumonia. ANIMAL STUDIES: Tumorigenic response after exposure of di-tert-butyl peroxide at a single dose of 100 umol to 50 mice consisted of 7 animals with malignant lymphomas and 1 animal with pulmonary adenomas out of 35 survivors. Di-t-butyl peroxide, which was essentially inactive in short-term in vitro promotion assays, was also totally inactive in promoting papillomas or carcinomas in initiated skin. Chromosome breakage has been detected using tert-butyl peroxide. The mutagenicity of di-t-butyl peroxide was tested using Salmonella typhimurium TA 98 and TA 100 in the presence of metabolic activation. No mutagenic activity was observed with di-t-butyl peroxide. Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Bioconcentration: An estimated BCF of 88 was calculated in fish for bis(1,1-dimethylethyl)peroxide(SRC), using an estimated log Kow of 3.45(1) and a regression-derived equation(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is moderate(SRC). Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Fate: TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 620(SRC), determined from a structure estimation method(2), indicates that bis(1,1-dimethylethyl)peroxide is expected to have moderate mobility in soil(SRC). Volatilization of bis(1,1-dimethylethyl)peroxide from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 0.0483 atm-cu m/mole(SRC), based upon its vapor pressure, 25.1 mm Hg(3), and water solubility, 100 mg/L(4). Bis(1,1-dimethylethyl)peroxide is expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(3). Utilizing the Japanese MITI test, 0% of the Theoretical BOD was reached in 4 weeks(4) indicating that biodegradation is not an important environmental fate process in soil(SRC). Organic peroxides, such as bis(1,1-dimethylethyl)peroxide, are strong oxidizers and may ignite organic materials in soil on contact(6). Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Fate: AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 620(SRC), determined from a structure estimation method(2), indicates that bis(1,1-dimethylethyl)peroxide is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 0.0483 atm-cu m/mole(SRC), derived from its vapor pressure, 25.1 mm Hg(4), and water solubility, 100 mg/L(5). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 4 hrs and 5 days, respectively(SRC). According to a classification scheme(6), an estimated BCF of 88(SRC), from an estimated log Kow of 32.45(2), suggests the potential for bioconcentration in aquatic organisms is moderate(SRC). Utilizing the Japanese MITI test, 0% of the Theoretical BOD was reached in 4 weeks(7) indicating that biodegradation is not an important environmental fate process in water(SRC). Organic peroxides, such as bis(1,1-dimethylethyl)peroxide, are strong oxidizers and may ignite organic materials in water on contact(8). Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Fate: ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), bis(1,1-dimethylethyl)peroxide, which has a vapor pressure of 25.1 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase bis(1,1-dimethylethyl)peroxide is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 15 days(SRC), calculated from its rate constant of 1.0X10-12 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Bis(1,1-dimethylethyl)peroxide absorbs UV light at wavelengths of 340 nm(4) and, therefore, may be susceptible to direct photolysis by sunlight(SRC). Source: Hazardous Substances Data Bank (HSDB)

Mapped by: Existing checksum-valid CAS to unique PubChem CID match. Retrieved: 2026-08-31. Open source record

Scientific classifications and hazard annotations provide context and do not replace the market-specific regulatory decision shown above.

Additional source coverage and match status
SourceResultChecked
NIH PubChem PUG-ViewExact match2026-08-31

A recorded no-match is useful evidence that the source was checked; it is not a claim that the substance does not exist elsewhere.

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Record details

Chemical name

Di-tert-butyl peroxide

Chemical / IUPAC name

Di-tert-butyl peroxide

Regulatory information

Regulation

(EU) 2019/831

See every entry this act set

CMR

CategoryCarcinogenicMutagenicReprotoxic
Cat. 2—✓—

Key data

CAS
110-05-4
EC
203-733-6
Annex
II
Entry number
1553

Direct matches are limited for this record, so nearby entries from Annex II are shown as well.

Annex II 1547
Nearby record in the same annex

Tetrahydrofuran

CAS: 109-99-9
EC: 203-726-8

What Annex II means for Di-tert-butyl peroxide

Di-tert-butyl peroxide is listed as a prohibited substance under Annex II of EU Cosmetics Regulation 1223/2009 and must not be intentionally added. Article 17 separately addresses unintended small quantities that are technically unavoidable under good manufacturing practice and compatible with the Article 3 safety requirement.

Formulators must screen their ingredients and raw materials to ensure none contain this substance. Suppliers should provide documentation confirming absence when requested.

The page also surfaces 12 related annex records with overlapping identifiers, annex logic or naming patterns.

Compliance checklist

  • Verify this substance is absent from all raw materials and finished formulations.
  • Request absence confirmation or CoA from raw material suppliers.
  • Document the screening result in the Product Information File (PIF).
  • This substance has CMR classification. Review the CMR table above and verify current Annex II/III status before use.

Frequently asked questions

Yes. Di-tert-butyl peroxide is listed in Annex II of EU Cosmetics Regulation 1223/2009 and is prohibited as an intentionally added cosmetic ingredient. Article 17 provides a narrow exception for unintended small quantities that are technically unavoidable under good manufacturing practice, provided the product remains safe under Article 3.

CAS 110-05-4 is the unique numerical identifier assigned to Di-tert-butyl peroxide by the Chemical Abstracts Service. In cosmetic compliance work, the CAS number is used to cross-reference the substance across regulatory databases, raw material specifications and safety assessment reports. Multiple EU annex entries may share the same CAS number if the same substance appears under different conditions or in different annexes.

Di-tert-butyl peroxide has a CMR (carcinogenic, mutagenic or reprotoxic) classification under EU CLP Regulation. Under Article 15 of EU Cosmetics Regulation 1223/2009, CMR substances of category 1A or 1B are prohibited in cosmetics unless specifically permitted. Category 2 CMR substances may be used only if assessed safe by the SCCS. Always verify current annex status and any applicable derogations before use.

Use the INCI Checker tool on this site to paste your full ingredient list (INCI) and scan it against all Annex II–VI entries. The tool highlights any ingredients that match restricted, prohibited or allergen-flagged records. This is useful for rapid compliance screening of finished product formulas or raw material declarations.
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Source note for Annex II record Di-tert-butyl peroxide

This page summarizes one Annex II record for Di-tert-butyl peroxide from public European Commission cosmetic materials and adds linked inventory or identifier matches when available.

Use this record page to review Annex II conditions for Di-tert-butyl peroxide, but confirm any final regulatory decision against the current official annex wording and source files.

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