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Annex II Entry 995 CMR23/11/2016

4-Nitrosophenol

4-Nitrosophenol is listed in Annex II as a prohibited substance for cosmetic products placed on the EU market.

Prohibited substance— Annex II, EU Regulation 1223/2009
Entry: 995
CMR

Chemical identity and properties

PubChem 2D chemical structure for CAS 104-91-6
CAS 104-91-6PubChem CID 7729

4-Nitrosophenol

P-benzoquinone monoxime is a black solid. (NTP, 1992) CAMEO Chemicals

IUPAC name
4-nitrosophenol
Molecular formula
C6H5NO2
Molecular weight
123.11 g/mol
Exact mass
123.032028402 Da
XLogP3
1.3
Topological polar surface area
49.7 Ų
Hydrogen-bond donors
1
Hydrogen-bond acceptors
3
Covalent units
1
Defined stereocentres
0

Also known as

p-NitrosophenolPhenol, 4-nitroso-Quinone monoximeNitrosophenolQuinone oximePhenol, p-nitroso-1,4-Benzoquinone monoximepara-Nitrosophenol
16 more reported names
55EB58H2UPNSC-3124RefChem:526027203-251-64-Benzoquinone Monoxime637-62-7p-Quinone monoximeQuinone monooxime1,4-Benzoquinone 4-oximep-Quinone monooxime4-NitrosofenolQuinone 4-oximep-Benzoquinone 4-oximep-Benzoquinone, monooximep-Chinonmonoximp-Benzoquinone monoxime
External database identifiers

Evidence from additional scientific databases

NIH PubChem PUG-View
Exact identifier match7729

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

  • Melting Point: 270 to 291 °F (decomposes) (NTP, 1992) Source: CAMEO Chemicals
  • 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: H302: Harmful if swallowed [Warning Acute toxicity, oral]; H318: Causes serious eye damage [Danger Serious eye damage/eye irritation]; H341: Suspected of causing genetic defects [Warning Germ cell mutagenicity]; H411: Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard] Source: Regulation (EC) No 1272/2008 of the European Parliament and of the Council
  • Precautionary Statement Codes: P203, P264, P264+P265, P270, P273, P280, P301+P317, P305+P354+P338, P317, P318, P330, P391, P405, 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: H242 (20.7%): Heating may cause a fire [Danger Self-reactive substances and mixtures; Organic peroxides]; H301 (11.7%): Toxic if swallowed [Danger Acute toxicity, oral]; H302 (88.3%): Harmful if swallowed [Warning Acute toxicity, oral]; H315 (56.4%): Causes skin irritation [Warning Skin corrosion/irritation]; H317 (55.9%): May cause an allergic skin reaction [Warning Sensitization, Skin]; H318 (100%): Causes serious eye damage [Danger Serious eye damage/eye irritation]; H341 (100%): Suspected of causing genetic defects [Warning Germ cell mutagenicity]; H411 (88.3%): Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]; H413 (11.7%): May cause long lasting harmful effects to aquatic life [Hazardous to the aquatic environment, long-term hazard] Source: European Chemicals Agency (ECHA)
  • Precautionary Statement Codes: P203, P210, P234, P235, P240, P261, P264, P264+P265, P270, P272, P273, P280, P301+P316, P301+P317, P302+P352, P305+P354+P338, P317, P318, P321, P330, P332+P317, P333+P317, P362+P364, P370+P378, P391, P403, 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 188 reports by companies from 8 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: Hazardous Chemical Information System (HCIS), Safe Work Australia
  • GHS Hazard Statements: H302: Harmful if swallowed [Warning Acute toxicity, oral]; H318: Causes serious eye damage [Danger Serious eye damage/eye irritation]; H341: Suspected of causing genetic defects [Warning Germ cell mutagenicity]; H411: Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard] Source: Hazardous Chemical Information System (HCIS), Safe Work Australia
  • Precautionary Statement Codes: P203, P264, P264+P265, P270, P273, P280, P301+P317, P305+P354+P338, P317, P318, P330, P391, P405, and P501 (click each P-code to see the statement) Source: Hazardous Chemical Information System (HCIS), Safe Work Australia

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
EMBL-EBI ChEBINo exact record2026-08-31
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

4-Nitrosophenol

Chemical / IUPAC name

4-Nitrosophenol

Regulatory information

Key data

Annex
Entry number
995

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

Annex II 996
Nearby record in the same annex

Carbendazim

CAS: 10605-21-7
EC: 234-232-0
Annex II 999
Nearby record in the same annex

Hexane

CAS: 110-54-3
EC: 203-777-6

What Annex II means for 4-Nitrosophenol

4-Nitrosophenol 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. 4-Nitrosophenol 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 104-91-6 is the unique numerical identifier assigned to 4-Nitrosophenol 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.

4-Nitrosophenol 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.

Source note for Annex II record 4-Nitrosophenol

This page summarizes one Annex II record for 4-Nitrosophenol 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 4-Nitrosophenol, but confirm any final regulatory decision against the current official annex wording and source files.

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