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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Taken from EU Risk Assessment Report - Reviewed by the Danish Environmental Protection Agency. Guideline Study.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2002

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
GLP compliance:
not specified
Test type:
standard acute method
Limit test:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
4-chloro-o-cresol
EC Number:
216-381-3
EC Name:
4-chloro-o-cresol
Cas Number:
1570-64-5
Molecular formula:
C7H7ClO
IUPAC Name:
4-chloro-2-methylphenol

Test animals

Species:
rat
Strain:
not specified
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Housing: caged
- Diet (e.g. ad libitum): conventional laboratory diet.
- Water (e.g. ad libitum): Ad libitium
- Acclimation period:At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C +/- 3°C
- Humidity (%): 30-70%
- Air changes (per hr): not specified
- Photoperiod (hrs dark / hrs light): 12hour light / 12 hours dark


Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
not specified
Vehicle:
other: 50% alcohol (alcohol not specified)
Analytical verification of test atmosphere concentrations:
not specified
Duration of exposure:
ca. 4 h
Concentrations:
Control: 0 mg/m3
Test concentrations : 5.79, 8.33, 9.11 and 10 % 4-chloro-o-cresol as an aerosol in 50% alcohol.
This equates to a concentration in air of 0.579 -1.08 mg/L
No. of animals per sex per dose:
5 male and 5 female rats per dose.
Control animals:
yes

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
ca. 0.9 mg/L air (nominal)
Exp. duration:
4 h
Remarks on result:
other: The range for mortalities was 0.83 - 1.08 mg/L (nominal)
Mortality:
All deaths occuring in the study occurred during exposure or within the first hour after exposure.
The details are summarised in Table 1 included in the remarks section below.
Clinical signs:
other: Symptoms observed during and after exposure were respiration difficulties, depressions, ruffled fur and bleeding from the nose. These symptoms were dose related. Petechiae of the lungs were also observed.
Gross pathology:
Examination of the animals that died within the first hour of dosing showed bleeding of the lungs and the small intestine was found to contain a thin yellowish mucus.

Any other information on results incl. tables

Table 1. Summary of Mortalities.

 Dose level, mg/L  Mortality/No in group
 0 (Control)  0/10
0.579   0/10
 0.833  2/10
 0.911 4/10 
 1.08 7/10 

Applicant's summary and conclusion

Interpretation of results:
other: toxic
Remarks:
Criteria used for interpretation of results: other: Approved Classification and Labelling Guide (Sixth Edition), Chemicals (Hazard Information and Packaging for Supply) Regulations 2009 (CHIP 4)
Conclusions:
Based on the results from this study 4-chloro-o-cresol is considered to be toxic by inhalation.
Executive summary:

A guideline study was performed on groups of 10 rats (5 male/5 female). The animals were exposed to the equivalent of 0, 0.579, 0.833, 0.911 and 1.08 mg/L of 4 -chloro-o-cresol administered as an aerosol in 50% alcohol.

All deaths during the study occurred during exposure or within the first hour after exposure.

The mortalities are summarised in the table below.

 Dose level, mg/L  Mortality/No in group
 0 (Control)  0/10
0.579   0/10
 0.833  2/10
 0.911 4/10 
 1.08 7/10 

Symptoms observed during and after exposure were respiration difficulties, depressions, ruffled fur and bleeding from the nose. These symptoms were dose related. Petechiae of the lungs were also observed.

Examination of the animals that died within the first hour of dosing showed bleeding of the lungs and the small intestine was found to contain a thin yellowish mucus.

The LD50 was determined to be 0.9 mg/L air.