Why does CAS 624-83-9 appear in more than one EU cosmetic annex?

A substance identified by CAS 624-83-9 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts — for example, restricted under Annex III with specific conditions, while also appearing in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

How do I check if my formula contains a substance with CAS 624-83-9?

Use the INCI Checker on CosIng Checker with INCI names, CAS numbers or EC numbers. Paste CAS 624-83-9 to screen it directly, then review every linked annex record and supplier document.

CAS 1 record

CAS 624-83-9

Q: How do I use CAS 624-83-9 for compliance screening?

Cross-reference CAS 624-83-9 against your raw material specification sheets and CoA documents. When it appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met. All annex entries sharing this CAS number are listed on this page.

CAS 624-83-9 matches 1 EU annex record across Annex II–VI of Regulation 1223/2009.

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Chemical identity and properties

PubChem 2D chemical structure for CAS 624-83-9

CAS 624-83-9PubChem CID 12228

Methyl Isocyanate

Methyl isocyanate is the isocyanate that is methane modified by a single isocyanato substituent. It has a role as an allergen and an apoptosis inducer. — ChEBI

IUPAC name: methylimino(oxo)methane

Molecular formula: C2H3NO
Molecular weight: 57.05 g/mol
Exact mass: 57.021463719 Da
XLogP3: 1.1
Topological polar surface area: 29.4 Å²
Hydrogen-bond donors: 0
Hydrogen-bond acceptors: 2
Covalent units: 1
Defined stereocentres: 0

Also known as

IsocyanatomethaneMethane, isocyanato-methylisocyanateMethyl carbonimideMethylcarbylamineIsocyanate de methyleIso-cyanatomethaneMethylisocyanaat

16 more reported names

Isocyanic acid, methyl esterMethyl isocyanatMetil isocianatoMethylisokyanatRCRA waste number P064TL 1450C588JJ4BV9methylimino-oxomethaneCHEBI:59059NSC-64323Methyl ester of isocyanic acidRefChem:6023210-866-3(Methylimino)(oxo)methaneNSC 64323UN 2480

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

ChEBI:CHEBI:59059
ChEMBL:CHEMBL1608558
EPA DTXSID:DTXSID1023786
PubMed:25251934
PubMed:22938400
PubMed:22931884
PubMed:22864532
PubMed:22819479
PubMed:22664494
PubMed:22471495
PubMed:22446861
PubMed:22408587
PubMed:22375795
PubMed:22375610
PubMed:22223508

Retrieved from NIH PubChem on 2026-08-31 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Records for CAS 624-83-9

1 total

Annex

Entry

1183

Methyl isocyanate

210-866-3

CMR

How CAS 624-83-9 is used on this site

CAS 624-83-9 is the Chemical Abstracts Service identifier used to pin this page to a specific substance. In the current dataset, 1 EU annex record shares this identifier, which helps you cross-check whether the same substance appears under one regulatory context or several.

Use this page when a supplier specification, SDS or raw-material dossier gives you CAS 624-83-9 and you need to see every linked Annex II–VI record in one place. The entry cards above are the quickest route to concentration limits, warnings, annex placement and product-type conditions.

Frequently asked questions

A substance identified by CAS 624-83-9 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts. For example, a substance might be restricted under Annex III with specific conditions, and the same CAS might also appear in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

Cross-reference the CAS number against your raw material specification sheets and CoA documents. When a CAS appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met in your formulation. All annex entries sharing this CAS number are listed above.

A CAS number is assigned by the Chemical Abstracts Service (USA) and is globally recognised. An EC number is a European Commission identifier from inventories such as EINECS, ELINCS or the NLP list. Both identifiers may appear in EU cosmetic annex entries. Some substances have both, some have only one, and some older entries may have neither.

The INCI Checker accepts ingredient names, CAS numbers and EC numbers. Check this CAS number directly, then verify the result against supplier specification sheets and every linked annex condition.

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