Warning GHS08GHS09 NOAEL Data SVHC REACH Registered Cosmetic Ingredient

Octamethylcyclotetrasiloxane

Also known as: Cyclotetrasiloxane, octamethyl-, D4, BRN 1787074, EINECS 209-136-7, Silicone SF 1173 (+6 more)

CAS 556-67-2

Octamethylcyclotetrasiloxane (CAS 556-67-2) is a chemical substance with GHS signal word Warning; key hazard signal: H361f ***; H410. Key regulatory status: SVHC Candidate List, REACH registered, 22 regulatory/inventory lists, cosmetic ingredient cross-reference; source data from ECHA CLP, EPA ToxValDB, EPA CPDat, AICIS, SCCS, ECHA REACH, ECHA SVHC, ILO ICSC.

View cosmetic safety profile for Cyclotetrasiloxane →

SOURCE NOAEL studies
NOAEL studies
48
SOURCE Chemical inventory jurisdictions
Regulatory lists
22
SOURCE EU CLP Annex VI
GHS signal
Warning

Chemical Identity

CAS, identifiers, formula, and alternate names for the matched substance record.

SOURCE DSSTox identifiers 16 fields
Name
Octamethylcyclotetrasiloxane
CAS Number
556-67-2
Molecular Formula
C8H24O4Si4
InChI Key
HMMGMWAXVFQUOA-UHFFFAOYSA-N
Monoisotopic Mass
296.075165
Synonyms
Cyclotetrasiloxane, octamethyl-D4BRN 1787074EINECS 209-136-7Silicone SF 1173OktamethylcyklotetrasiloxanUNII-CZ227117JE2,2,4,4,6,6,8,8-octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane2,2,4,4,6,6,8,8-octamethyl-1,3,5,7,2,4,6,8-tetroxatetrasilocaneOktamethylzyklotetrasiloxancyclic dimethylsiloxane tetramer

Substance of Very High Concern (SVHC)

Candidate List status and reason under the ECHA REACH SVHC program.

SOURCE ECHA 1 records
SubstanceReasonIncluded
OctamethylcyclotetrasiloxanePBT (Article 57d); vPvB (Article 57e)27-Jun-2018

GHS / CLP Classification

EU harmonized hazard classification, hazard statements, pictograms, and signal word.

SOURCE EU CLP Annex VI (ECHA) 1 classifications
Hazard ClassH-StatementsPictogramsSignal
Repr. 2; Aquatic Chronic 1H361f ***; H410GHS08; GHS09Warning

ICSC Chemical Safety

International Chemical Safety Card hazard and exposure summary.

SOURCE WHO/JECFA 1 records
FieldValue
Routes of ExposureThe substance can be absorbed into the body by inhalation of its vapour, through the skin and by ingestion.

Functional Uses

Industrial and product-use categories associated with this substance.

SOURCE EPA CPDat 38 records
SolventSurfactant (surface active agent)Processing aids not otherwise specifiedWetting agent (non-aqueous)Defoamer

Regulatory Lists

Inventory, screening, and regulatory list matches from public chemical databases.

SOURCE EPA CPDat 22 records
ListKeywordSource
children; Europe; Personal careDanish Environmental Protection AgencyDanish EPA
inert_ingredient; non_food_use; PesticidesEPACPCat
detected; Europe; Personal care - general moisturizing - hand/body lotion; Personal care - sunscreenDanish Environmental Protection AgencyDanish EPA
Europe; Toys and children's productsDanish Environmental Protection AgencyDanish EPA
detected; Europe; Other direct contact consumer goods; Toys and children's productsDanish Environmental Protection AgencyDanish EPA
detected; Europe; Other direct contact consumer goods; Toys and children's productsDanish EPADanish EPA
consumer_product; EuropeDanish Environmental Protection AgencyDanish EPA
Europe; Raw materialsDanish Environmental Protection AgencyDanish EPA
Europe; Other direct contact consumer goodsDanish Environmental Protection AgencyDanish EPA
childrenVermont Department of HealthState of Vermont
childrenMaine Department of Environmental ProtectionState of Maine
EuropeEuropean Chemicals AgencyEuropean Chemicals Agency (ECHA)
banned; Europe; Personal careEuropean CommissionCosIng
EuropeDanish Environmental Protection AgencyDanish EPA
detected; Toys and children's productsState of Washington Department of EcologyState of Washington
Arts and crafts/Office supplies - children's art and toys; detectedState of Washington Department of EcologyState of Washington
detected; Personal care - child specific; Toys and children's productsState of Washington Department of EcologyState of Washington
detected; Personal careState of Washington Department of EcologyState of Washington
detected; Toys and children's productsState of Washington Department of EcologyState of Washington
detected; Toys and children's productsState of Washington Department of EcologyState of Washington
detected; Toys and children's productsState of Washington Department of EcologyState of Washington
banned; Europe; Personal careEuropean CommissionCosIng

NOAEL Studies

Toxicology endpoints rendered from public NOAEL study rows.

SOURCE NOAEL studies Showing 48 of 48 studies
ValueUnitEndpointRouteSpeciesSource
=0.1mg/kg bw/day-oralratRegulatory source
=0.2mg/kg bw/day-oralratRegulatory source
5ppm-inhalationratRegulatory source
5%-inhalationratRegulatory source
10ppm--ratRegulatory source
10ppm---Regulatory source
11----Regulatory source
=17.8mg/kg bw/day-oralratRegulatory source
35ppm--ratRegulatory source
50ppm-inhalationratRegulatory source
52%-oralratRegulatory source
70ppm-oralratRegulatory source
100mg/kg-oralratRegulatory source
>132ppm---Regulatory source
150ppm---Regulatory source
150ppm--ratRegulatory source
150ppm-inhalationratRegulatory source
150ppm-oral-Regulatory source
<226ppm--mouseRegulatory source
<226ppm-inhalationmouseRegulatory source
300ppm--ratRegulatory source
=300ppm-inhalationratRegulatory source
700ppm--ratRegulatory source
=73mg/m3DNEL localinhalationHumanToxValDB GESTIS DNEL
CZ227117JEUNIIFDA UNII substance identifier--openFDA substances
36mg/LLC50Inhalation-NTP ICE acute inhalation
=1540mg/kg bwLD50oralRatNTP ICE acute oral
>4800mg/kg bwLD50oralRatNTP ICE acute oral
>6.144e+4mg/kg bwLD50oralRatNTP ICE acute oral
=250mg/kg bw/dayLELoralRatToxValDB Uterotrophic Hershberger DB
=849.2mg/m3LELinhalationRatToxValDB EPA TSCA 8e
=1000mg/kg bw/dayLELoralMouseToxValDB Uterotrophic Hershberger DB
=8492mg/m3LELinhalationRatToxValDB EPA TSCA 8e
60mg/kg bw/dayLOAELoralmouseCOSMOS DB
210mg/kg bw/dayLOAELoralratCOSMOS DB
335mg/kg bw/dayLOAELoralratCOSMOS DB
745mg/kg bw/dayLOAELoralmouseCOSMOS DB
250mg/kg bw/dayLOELOralRatNTP ICE endocrine
0unitlessModel Score--NTP ICE endocrine
=0.1mg/kg bw/dayNOAELdermalratSCCS Opinion
=0.2mg/kg bw/dayNOAELoralratSCCS Opinion
=4-NOAELinhalationratSCCS Opinion
=5ppmNOAELinhalationratSCCS Opinion
=10ppmNOAEL-ratSCCS Opinion
=11-NOAEL--SCCS Opinion
=17.8mg/kg bw/dayNOAELoralratSCCS Opinion
=35ppmNOAEL-ratSCCS Opinion
=50ppmNOAELinhalationratSCCS Opinion

Showing 48 of 48 studies

REACH Registration

Registration status from the ECHA REACH registered substances database.

SOURCE ECHA 1 records
StatusNameEC NumberLink
RegisteredOctamethylcyclotetrasiloxane209-136-7ECHA overview →

Australian Status (AICIS)

Australian industrial chemicals inventory status and applicable conditions.

SOURCE AICIS inventory 1 records
Inventory Status
listed

SCCS Opinions

EU Scientific Committee opinions tied to the matched substance.

SOURCE SCCS Opinion 2 opinions
OpinionDateConclusionMax Conc.Concerns
SCCP/0925/0513 December 2005Safe in cosmetics at reported use levels2005: safe in cosmetic products; D4 subsequently restricted under REACH for environmental reasons; endocrine activity under scrutiny
SCCP/0893/052005-12-13On the basis of provided data, the SCCP is unable to assess the risk to consumers when Octamethylcyclotetrasiloxane (D4) is used in cosmetic products.-Dossier lacked meaningful information/data on actual consumer exposure to D4. Required: adequate use information; relevant percutaneous absorption studies at different use concentrations; information on co-use/consumer exposure of related organosiloxanes, in particular decamethylcyclopentasiloxane (D5).

Cosmetic Safety Profile

Same-CAS cosmetic ingredient record for cross-vertical context.

SOURCE CosIng / Ingredients DB
EU Status
restricted
Max
≥0.1% w/w prohibited in all consumer and professional products under EU Reg 2024/1328; enforcement June 6, 2026
Category
volatile-silicone
View full cosmetic safety profile →

Pharmaceutical Data

Same-CAS pharmaceutical records from drug and bioactivity sources.

SOURCE ChEMBL / DailyMed CHEMBL1869229
ChEMBL Phase
Not listed
Adverse Events
0
Bioactivity
1
View full pharmaceutical profile →

Cannabis Data

Same-CAS cannabis compliance and lab records where available.

SOURCE Cannabis regulatory / lab data efsa substances

1 cannabis record found in efsa substances.

View full cannabis profile →

Frequently Asked Questions

What is the GHS hazard classification for Octamethylcyclotetrasiloxane?

Octamethylcyclotetrasiloxane (CAS 556-67-2) is classified under EU CLP Annex VI as Repr. 2; Aquatic Chronic 1 with signal word Warning. Hazard statements: H361f ***; H410. Source: EU CLP Annex VI (ECHA).

What is the NOAEL for Octamethylcyclotetrasiloxane?

Octamethylcyclotetrasiloxane has 48 NOAEL studies in the database. The lowest reported value is 0 unitless. Source: NTP ICE endocrine.

What regulatory lists include Octamethylcyclotetrasiloxane?

Octamethylcyclotetrasiloxane appears on 15 regulatory/inventory lists including children; Europe; Personal care, inert_ingredient; non_food_use; Pesticides, detected; Europe; Personal care - general moisturizing - hand/body lotion; Personal care - sunscreen, and 12 more. Source: EPA CPDat.

Is Octamethylcyclotetrasiloxane a Substance of Very High Concern (SVHC)?

Yes, Octamethylcyclotetrasiloxane is listed on the ECHA REACH Candidate List as a Substance of Very High Concern. Reason: PBT (Article 57d); vPvB (Article 57e). Source: ECHA SVHC Candidate List.

Is Octamethylcyclotetrasiloxane used in cosmetics?

Yes, Octamethylcyclotetrasiloxane is also indexed as a cosmetic ingredient under the name Cyclotetrasiloxane. View the full cosmetic safety profile on the ingredient page for detailed safety data, SCCS opinions, and regulatory status.

Where does the safety data for Octamethylcyclotetrasiloxane come from?

Safety data is sourced from ECHA CLP Annex VI, EPA ToxValDB, EPA CPDat, AICIS (Australian Industrial Chemicals Introduction Scheme), EPA DSSTox, ECHA REACH, ECHA SVHC Candidate List, ILO/WHO ICSC, CosIng / Ingredients DB, ChEMBL / DailyMed, cannabis regulatory/lab databases. All data traces to primary regulatory sources and is updated from official government databases.

Does Octamethylcyclotetrasiloxane have different safety status in cosmetics vs industrial chemicals?

Octamethylcyclotetrasiloxane is classified GHS CMR hazard (H361f, H410) in the chemicals database but is restricted in EU cosmetics at max ≥0.1% w/w prohibited in all consumer and professional products under EU Reg 2024/1328; enforcement June 6, 2026.

Is Octamethylcyclotetrasiloxane used outside industrial chemicals?

Octamethylcyclotetrasiloxane also appears in cosmetics, pharmaceutical, cannabis databases.