Why does CAS 56-38-2 appear in more than one EU cosmetic annex?

A substance identified by CAS 56-38-2 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 56-38-2?

Use the INCI Checker on CosIng Checker with INCI names, CAS numbers or EC numbers. Paste CAS 56-38-2 to screen it directly, then review every linked annex record and supplier document.

CAS 1 record

CAS 56-38-2

Q: How do I use CAS 56-38-2 for compliance screening?

Cross-reference CAS 56-38-2 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 56-38-2 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 56-38-2

CAS 56-38-2PubChem CID 991

Parathion

Parathion is an organothiophosphate insecticide, a C-nitro compound and an organic thiophosphate. It has a role as an acaricide, an agrochemical, an avicide, an EC 3.1.1.8 (cholinesterase) inhibitor, an EC 3.1.1.7 (acetylcholinesterase) inhibitor and a mouse metabolite. It is functionally related to a 4-nitrophenol. — ChEBI

IUPAC name: diethoxy-(4-nitrophenoxy)-sulfanylidene-lambda5-phosphane

Molecular formula: C10H14NO5PS
Molecular weight: 291.26 g/mol
Exact mass: 291.03303072 Da
XLogP3: 3.8
Topological polar surface area: 106.0 Å²
Hydrogen-bond donors: 0
Hydrogen-bond acceptors: 6
Covalent units: 1
Defined stereocentres: 0

Also known as

ethyl parathionParathion-ethylThiophosalkronParaphosdanthionphosphostigminestathion

16 more reported names

AphamiteFosfernoRhodiatoxAlleronEtilonFolidolParawetPhoskilNirancorothioncorthionefosfivefosovagearphosgenithionkolphos

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

ChEBI:CHEBI:27928
ChEMBL:CHEMBL261919
EPA DTXSID:DTXSID7021100
PubMed:40419014
PubMed:36058312
PubMed:35435491
PubMed:34813904
PubMed:34778934
PubMed:33844597
PubMed:31675560
PubMed:30978295
PubMed:28927721
PubMed:28803989
PubMed:28174098
PubMed:26215119

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 56-38-2

1 total

Annex

Entry

131

O,O'-Diethyl-O-4-nitrophenyl phosphorothioate (Parathion - ISO)

200-271-7

How CAS 56-38-2 is used on this site

CAS 56-38-2 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 56-38-2 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 56-38-2 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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