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Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
skin irritation / corrosion, other
Remarks:
classification based on calculation rules for mixtures of the CLP Regulation
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
Classification based on calculation rules for mixtures of the CLP Regulation
Constituants data come from an online compilation using secondary data sources.

Data source

Referenceopen allclose all

Reference Type:
review article or handbook
Title:
Unnamed
Year:
2000
Report date:
2000
Reference Type:
other: Harmonized classification
Title:
Unnamed
Year:
2008
Report date:
2008

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Principles of method if other than guideline:
This method provides information on health hazard likely to arise from exposure to liquid or solid test substance by dermal application
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Thymol
EC Number:
201-944-8
EC Name:
Thymol
Cas Number:
89-83-8
Molecular formula:
C10H14O
IUPAC Name:
5-(2-propenyl)-1,3-benzodioxole

Test animals

Species:
rabbit
Strain:
not specified
Details on test animals or test system and environmental conditions:
6 adult albino rabbits (3.0 to 3.4 kg)

Test system

Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
water
Amount / concentration applied:
500mg
Duration of treatment / exposure:
1, 24, 48 and 72 hours
Observation period:
7 days and 14 days
Number of animals:
6 adult of both sexes

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
erythema score
Basis:
mean
Time point:
24/48/72 h
Max. score:
4
Reversibility:
not reversible
Remarks on result:
probability of severe irritation
Irritation parameter:
edema score
Basis:
mean
Time point:
24/48/72 h
Max. score:
4
Reversibility:
not reversible
Remarks on result:
probability of severe irritation
Irritant / corrosive response data:
"The primary skin irritancy of thymol (99.5% pure) was tested in 6 adult albino rabbits (3.0 to 3.4 kg) of both sexes in accordance with OECD guideline No. 404. They underwent a single semi-occlusive 4-hour exposure to 500mg of the test substance, made into a paste with water and applied to themechanically depilated flank skin. The findings were scored 1, 24, 48 and 72 hours as well as 7 and 14 days after the end of exposure. Thymol proved corrosive in all of the animals. The necrotic changes were irreversible in all of the animals up to the end of the observation period (Bayer, 1986 b)."

Applicant's summary and conclusion

Interpretation of results:
Category 1B (corrosive) based on GHS criteria
Conclusions:
After the end of exposure, thymol proved corrosive in all of the animals. The necrotic were irreversible in all of the animals up to the end of the observation period.
Moreover, thymol is listed is annex 6 of European Regulation 1272/2008 and the hazard class is Skin corr. 1B and is classified H314.
The classification of thymol is category 1B according to CLP and GHS criteria.
No study was conducted on the thyme oil iself.
The test item is a natural complex substance (NCS). It is a mixture of several constituents, and thymol represents about 51% of this UVCB substance.
Literature above provided data for this major compound.
Executive summary:

The NCS is composed of several identified constituents, so it can be considered as a mixture according to the definition of the CLP Regulation. The decision logic for classification of mixtures from the ECHA Guidance on the Application of the CLP Criteria (2015) was used to determine the skin irritation / corrosion potential of the registered substance.

The registered substance has not been tested itself in appropriate in vitro or in vivo tests.

But one of its constituents is classified as skin corrosive (thymol at 51%).

The single constituent is present above the CLP generic concentration limit of 5% that triggers classification of the mixture. Therefore, the registered substance is classified as a skin corrosive substance without further testing according to the Regulation (EC) No 1272/2008