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EC number: 216-835-0 | CAS number: 1678-91-7
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Endpoint summary
Administrative data
Description of key information
Acute oral toxicity:
An acute oral toxicity study was conducted in male and female rats administered a single limit dose of 2000 mg/kg of the test material by gavage. Discolored (light-brown) feces were noted from all animals on the day following dosing. No other abnormal clinical signs were observed during the 14-day observation period. No mortality was observed, and all animals gained weight normally. Treatment-related changes observed at necropsy were limited to minimal hyperkeratosis of the non-glandular gastric mucosa. for all males and three of five females. No other treatment-related changes or signs of organ toxicity were noted at necropsy. In the absence of significant gross organ lesions, other than the obvious signs of gastric irritation, no tissue was collected for histological examination. The acute oral LD50 for this test material was greater than 2000 mg/kg for male and female rats.
Acute dermal toxicity:
A limit dose of 2000 mg/kg was applied to the skin after the hair was removed with an electric clipper. An occlusive wrap was used to hold the test material against the skin for a period of 24 hours, and at the end of exposure, residual test material was washed off with running water.
No treatment-related abnormal clinical signs were evident at any time during the 14-day observation period. On the last day of the observation period, a small wound with a scab was noted on the shoulder of a single male (Rat 745). Since this animal had appeared clinically normal from the day of dosing to Day 13, this wound was not considered related to administration of the test material. No treatment-related changes or signs of organ toxicity were evident at necropsy. In the absence of significant gross organ lesions, no tissue was collected for histological examination. Based on weight gain and survival rate, there was no evidence of percutaneous absorption. The acute dermal LD50 for this test material was greater than 2000 mg/kg for both sexes.
Acute inhalation toxicity: Data from the read-across substance methylcyclohexane is available:
Health Council of the Netherlands:
When rats were exposed to vapour concentrations of 82,000-260,000 mg/m3 (ca. 20,000-62,000 ppm), mortality occurred within 13-70 minutes, animals showing anaesthesia, lethargy, ataxia, and terminal convulsion. Exposure to 11,000 mg/m3 (ca. 2600 ppm), for 6 hours, induced only minor symptoms (lethargy in 3 hours)
CDC:
In mice, a 2-hour LC50 of 41,500 mg/m3 (ca. 10,000 ppm) is reported. No detailed study description is given.
Publication Treon:
In this rabbit study, all the animals died at 59.9 mg/L within 70 min after exposure initiation. LC50 was considered as between 39.6 and 59.9 mg/L. Signs of toxicity at 59.9 mg/L (70 min exposure) included severe convulsions, rapid narcosis, labored breathing, salivation, and conjunctival congestion.
Since it was judged in the SIDS INITIAL ASSESSMENT PROFILE for the Methyl-Ethylcyclohexane Category that the read across from methyl- to ethylcyclohexane is plausible and can be proven by the similarity in structure and physicochemical properties, it is assumed that ethylcyclohexane will behave in a similar manner with respect to acute inhalation toxicity.
Based on the narcotic effects observed in the available studies for methylcyclohexane at high concentration classification of methylcyclohexane according to Regulation (EC) No 1272/2008 as STOT-SE 3 (narcotic effects) is fully justified.
Therefore ethylcyclohexane will be classified as STOT-SE 3 (narcotic effects) too.
Key value for chemical safety assessment
Acute toxicity: via oral route
Link to relevant study records
- Endpoint:
- acute toxicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 1992-01-20 - 1992-04-03
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 401 (Acute Oral Toxicity)
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Test type:
- fixed dose procedure
- Limit test:
- yes
- Specific details on test material used for the study:
- SRI1D or Lot I.D. Number: 7482-9A
Physical State and Appearance: Colorless liquid - Species:
- rat
- Strain:
- other: CD(SD)BR VAF/Plus
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- Housing:
All animals were individually housed in suspended, stainless-steel, mesh cages.
Environmental Conditions:
A photoperiod of 12 hours light from 6 a.m. to 6 p.m. Room temperature was maintained at
74-75*F. Relative humidity was maintained-at 45-47%.
Diet and Water:
ad libitum - Route of administration:
- oral: gavage
- Vehicle:
- unchanged (no vehicle)
- Details on oral exposure:
- A single dose of the test material was administered by gavage to animals that had been fasted
overnight. - Doses:
- 2000 mg compound/kg body weight
- No. of animals per sex per dose:
- 5 males, 5 females
- Control animals:
- no
- Details on study design:
- Clinical Observations:
Animals were observed at least three times on the day of dosing (Day 0), and once each workday thereafter for the duration of the experiment (a total of 14 calendar days). Observation included, but was not limited to: examination of the hair, skin, eyes, motor activity, feces, and urine. Animals were checked for mortality on weekend days.
Body Weight Determinations:
Body weights were collected on the day of dosing (Day 0), Day 7, and Day 14 of the study.
Necrosy:
All animals were necropsied at the completion of the 14-day observation period. - Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- > 2 000 mg/kg bw
- Based on:
- test mat.
- Mortality:
- none
- Clinical signs:
- other: Discolored (light-brown) feces were noted from all animals on the day following dosing.
- Gross pathology:
- Minimal hyperkeratosis of the non-glandular gastric mucosa. for all males and three of five females.
- Interpretation of results:
- GHS criteria not met
- Conclusions:
- The test material was a gastric irritant as evidenced by hyperkeratosis of the non-glandular gastric mucosa. The acute oral LD50 for this test material was greater than 2000 mg/kg for male and female rats.
- Executive summary:
An acute oral toxicity study was conducted in male and female rats administered a single limit dose of 2000 mg/kg of the test material by gavage. Discolored (light-brown) feces were noted from all animals on the day following dosing. No other abnormal clinical signs were observed during the 14-day observation period. No mortality was observed, and all animals
gained weight normally. Treatment-related changes observed at necropsy were limited to minimal hyperkeratosis of the non-glandular gastric mucosa for all males and three of five females. No other treatment-related changes or signs of organ toxicity were noted at necropsy. In the absence of significant gross organ lesions, other than the obvious signs of
gastric irritation, no tissue was collected for histological examination.
Reference
Summary Table
DOSE (mg/kg) |
NUMBER OF RATS DOSED (M,F) |
NUMBER OF DEATHS <M,F) |
TIME OF DEATH |
WEIGHT GAIN* (M,F) |
|
I WEEK |
2WEEKS |
||||
2000 |
5,5 |
0,0 |
— |
5 +,5 + |
5 +,5 + |
*+ =Number of animals gaining weight -=Number of animals losing weight
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- LD50
- Value:
- 2 000 mg/kg bw
- Quality of whole database:
- The reported study is Guideline and GLP compliant.
Acute toxicity: via inhalation route
Link to relevant study records
- Endpoint:
- acute toxicity: inhalation
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Study period:
- 1943
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- study well documented, meets generally accepted scientific principles, acceptable for assessment
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- Determination of the minimum lethal concentration after repeated inhalation exposure
- GLP compliance:
- not specified
- Test type:
- other: minimum lethal concentration
- Limit test:
- no
- Specific details on test material used for the study:
- Purity: 97%
- Species:
- rabbit
- Strain:
- not specified
- Sex:
- not specified
- Route of administration:
- inhalation: vapour
- Type of inhalation exposure:
- whole body
- Vehicle:
- air
- Details on inhalation exposure:
- exposure chamber:
higher concentrations: 223 l metal cage
long-term inhalation at lower concentrations: battery of nine insulated plywood cages, capacity 600 l.
temperature: 23.9 ± 1.7 °C
humidity: <45%
air flow rate: 350 to 800 liters/minute
vapour generator: Bosch fuel injection pump - Analytical verification of test atmosphere concentrations:
- yes
- Duration of exposure:
- 6 h
- Remarks on duration:
- 6 hours per day
- Concentrations:
- 0.948, 1.46,4.57 mg/l: 300 hours
11.35 mg/l: 90 hours
21.90 mg/l: 120 hours
28.75, 39.55 mg/l: 60 hours
59.9 mg/L: 1 1/5 hours - No. of animals per sex per dose:
- 4
- Control animals:
- yes
- Key result
- Sex:
- not specified
- Dose descriptor:
- LC100
- Effect level:
- 59.9 mg/L air
- Based on:
- test mat.
- Exp. duration:
- 70 min
- Key result
- Sex:
- not specified
- Dose descriptor:
- other: mortality
- Effect level:
- 28.75 - < 39.55 mg/L air
- Based on:
- test mat.
- Exp. duration:
- 6 h
- Key result
- Sex:
- not specified
- Dose descriptor:
- other: minimum narcotic concentration
- Effect level:
- 21.9 mg/L air
- Based on:
- test mat.
- Exp. duration:
- 6 h
- Mortality:
- 0.948 - 21.90 mg/L: none
28.75 and 39.55 mg/L: mortality in 1/4 and 4/4 animals, respectively, after 2 weeks of exposure.
59.9 mg/L: mortality in 4/4 within 70 min after exposure initiation - Clinical signs:
- other: 0.948 - 11.35 mg/L: no effects 21.90 mg/L: slight lethargy. 28.75 mg/L: lethargy and impaired coordination of legs 39.55 mg/L: convulsions, light narcosis, laboured breathing, salivation, conjunctival congestion 59.55 mg/L: severe convulsions, rapid narco
- Body weight:
- Animals exposed to non-lethal concentrations gained weight. Mean group body weight gains were:
0.948 mg/L: 752 g (after 10 weeks)
4.57 mg/L: 956g (after 10 weeks)
11.35 mg/L: 328 g (after 3 weeks)
21.90 mg/L: 201 g (after 4 weeks)
Animals exposed to lethal concentrations lost weight. Mean group body weight gains were:
28.75 mg/L: -39 g (after 2 weeks)
39.55 mg/L: -390 g (after 2 weeks) - Gross pathology:
- Histopathology: After a 3-week exposure to 11.35 mg/L barely demonstrable evidence of cellular liver and kidney injury was reported.
Potential target organs: CNS at high concentrations - Interpretation of results:
- other: STOT-SE 3 H336 May cause drowsiness and dizziness
- Conclusions:
- In this rabbit study, all the animals died at 59.9 mg/L within 70 min after exposure initiation. LC50 was considered as between 39.6 and 59.9 mg/L. Signs of toxicity at 59.9 mg/L (70 min exposure) included severe convulsions, rapid narcosis, labored breathing, salivation, and conjunctival congestion.
- Executive summary:
In this rabbit study, all the animals died at 59.9 mg/L within 70 min after exposure initiation. LC50 was considered as between 39.6 and 59.9 mg/L. Signs of toxicity at 59.9 mg/L (70 min exposure) included severe convulsions, rapid narcosis, labored breathing, salivation, and conjunctival congestion.
In this study, mortality after single and repeated exposure occurred only at high to very high concentrations of methylcyclohexane, which are above the currently valid LC50 ranges used for classification. Therefore, the study results do not fulfil the classification criteria for acute toxicity by inhalation. Based on the narcotic effects consistently observed at high concentrations in this and further studies (Weight of Evidence), methylcyclohexane fulfils the classification criteria for Specific target organ toxicity-single exposure (STOT-SE) Category 3 (narcotic effects).
- Endpoint:
- acute toxicity: inhalation
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Study period:
- 2005
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- abstract
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- Acute inhalation toxicity study in mice
- GLP compliance:
- not specified
- Test type:
- other: not specified
- Limit test:
- no
- Species:
- mouse
- Strain:
- not specified
- Sex:
- not specified
- Route of administration:
- inhalation: vapour
- Type of inhalation exposure:
- not specified
- Vehicle:
- not specified
- Analytical verification of test atmosphere concentrations:
- not specified
- Duration of exposure:
- 2 h
- Control animals:
- not specified
- Sex:
- not specified
- Dose descriptor:
- LC50
- Effect level:
- 10 172 ppm
- Based on:
- test mat.
- Exp. duration:
- 2 h
- Sex:
- not specified
- Dose descriptor:
- LC50
- Effect level:
- 41.5 mg/L air
- Based on:
- test mat.
- Exp. duration:
- 2 h
- Interpretation of results:
- GHS criteria not met
- Conclusions:
- In mice, a 2-hour LC50 of 41,500 mg/m3 (ca. 10,000 ppm) is reported. No detailed study description is given.
- Executive summary:
In mice, a 2-hour LC50 of 41,500 mg/m3 (ca. 10,000 ppm) is reported. No detailed study description is given.
- Endpoint:
- acute toxicity: inhalation
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Study period:
- 2005
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- other: only short abstract
- Justification for type of information:
- Read across justification:
For justification of read across rationale see SIDS INITIAL ASSESSMENT PROFILE: Methyl/Ethylcyclohexane Category: available at:
webnet.oecd.org/HPV/UI/handler.axd?id=05fc63c8-e637-45aa-b3ff-6c19545e6c76
Citation from OECD SIDS:
"Category rationale (citation):
The methyl-ethylcyclohexane category consists of two chemicals which are methylcyclohexane and ethylcyclohexane. Both of the chemicals have a cyclohexane-ring as a basic molecular structure, and either a methyl functional group (-CH3) or an ethyl functional group (-CH2-CH3) is directly connected to this ring. Both chemicals are liquid at standard temperature and pressure. Based on the close similarity of molecular structures, all physical-chemical properties are similar.
There are a number of unifying considerations, which justify the inclusion of these two chemicals within the same category. These include:
1. Similarity of molecular structure and functional group:
These chemicals have a similar structure which is a direct connection of either methyl functional group (-CH3) or an ethyl functional group (-CH2-CH3) to the cyclohexane ring.
2. Similarity of physical-chemical properties:
All physical-chemical properties, especially water solubility, vapour pressure and log Kow are similar.
3. Similarity in health effects:
Toxicokinetic properties are similar.
Target organs of repeated dose toxicity are the liver and kidney for both chemicals.
Both chemicals show negative results of genotoxicity.
4. Similarity of environmental fate and distribution:
Both chemicals show the same or similar tendency in their environmental distribution, and biodegradation, which leads to the same behavior for these chemicals in the real environment.
5. Similarity of eco-toxicity:
Aquatic toxicity to fish (acute), daphnid (acute) and algae (acute and chronic) for both chemicals are very similar.
Analogue rationale:
Skin sensitization data of cyclohexane (CAS: 110-82-7) were used for the read across approach based on the similarity of structure. Cyclohexane is a basic molecular structure of methyl and ethylcyclohexenes." - Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- Acute inhalation toxicity study in rats
- GLP compliance:
- no
- Test type:
- acute toxic class method
- Limit test:
- no
- Species:
- rat
- Strain:
- not specified
- Sex:
- not specified
- Route of administration:
- inhalation: vapour
- Type of inhalation exposure:
- not specified
- Vehicle:
- not specified
- Analytical verification of test atmosphere concentrations:
- not specified
- Duration of exposure:
- 6 h
- Concentrations:
- 82-260 mg/l
- No. of animals per sex per dose:
- not specified
- Control animals:
- not specified
- Sex:
- not specified
- Dose descriptor:
- LC100
- Effect level:
- >= 82 - <= 260 mg/L air
- Based on:
- test mat.
- Remarks on result:
- other: mortality occurred within 13-70 min
- Sex:
- not specified
- Dose descriptor:
- LC0
- Effect level:
- 11 mg/L air
- Exp. duration:
- 6 h
- Mortality:
- 11 mg/L: no mortality occurred
82-260 mg/L: mortality occurred within 13-70 minutes - Clinical signs:
- other: 11 mg/L: only minor symptoms (lethargy in 3 hours) 82-260 mg/L: anaesthesia, lethargy, ataxia, and terminal convulsion
- Interpretation of results:
- other: STOT-SE 3 H336 May cause drowsiness and dizziness
- Conclusions:
- When rats were exposed to vapour concentrations of 82,000-260,000 mg/m3 (ca. 20,000-62,000 ppm), mortality occurred within 13-70 minutes, animals showing anaesthesia, lethargy, ataxia, and terminal convulsion. Exposure to 11,000 mg/m3 (ca. 2600 ppm), for 6 hours, induced only minor symptoms (lethargy in 3 hours)
Based on the narcotic effects observed in this study at high concentration classification of methylcyclohexane according to Regulation (EC) No 1272/2008 as STOT-SE 3 (narcotic effects) is fully justified. - Endpoint:
- acute toxicity: inhalation
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- weight of evidence
- Study period:
- 2005
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- other: only short summary
- Justification for type of information:
- Justification for Read Across from methycyclohexane:
The methyl-ethylcyclohexane category was category has been agreed by OECD member countries and was evaluated and justified in the OECD SIDS INITIAL ASSESSMENT PROFILE (available at: http://webnet.oecd.org/HPV/UI/handler.axd?id=05fc63c8-e637-45aa-b3ff-6c19545e6c76).
Citation from "SIDS INITIAL ASSESSMENT PROFILE-Methyl/Ethylcyclohexane Category":
"Category rationale (citation):
The methyl-ethylcyclohexane category consists of two chemicals which are methylcyclohexane and ethylcyclohexane. Both of the chemicals have a cyclohexane-ring as a basic molecular structure, and either a methyl functional group (-CH3) or an ethyl functional group (-CH2-CH3) is directly connected to this ring. Both chemicals are liquid at standard temperature and pressure. Based on the close similarity of molecular structures, all physical-chemical properties are similar.
There are a number of unifying considerations, which justify the inclusion of these two chemicals within the same category. These include:
1. Similarity of molecular structure and functional group:
These chemicals have a similar structure which is a direct connection of either methyl functional group (-CH3) or an ethyl functional group (-CH2-CH3) to the cyclohexane ring.
2. Similarity of physical-chemical properties:
All physiccal-chemical properties, especially water solubility, vapour pressure and log Kow are similar.
3. Similarity in health effects:
Toxicokinetic properties are similar.
Target organs of repeated dose toxicity are the liver and kidney for both chemicals.
Both chemicals show negative results of genotoxicity.
4. Similarity of environmental fate and distribution:
Both chemicals show the same or similar tendency in their environmental distribution, and biodegradation, which leads to the same behavior for these chemicals in the real environment.
5. Similarity of eco-toxicity:
Aquatic toxicity to fish (acute), daphnid (acute) and algae (acute and chronic) for both chemicals are very similar" - Reason / purpose for cross-reference:
- read-across source
- Qualifier:
- no guideline followed
- GLP compliance:
- no
- Test type:
- acute toxic class method
- Limit test:
- no
- Species:
- rat
- Strain:
- not specified
- Sex:
- not specified
- Route of administration:
- inhalation: vapour
- Type of inhalation exposure:
- not specified
- Vehicle:
- not specified
- Duration of exposure:
- 6 h
- Sex:
- not specified
- Dose descriptor:
- LC0
- Effect level:
- 11 mg/L air
- Based on:
- test mat.
- Exp. duration:
- 6 h
- Sex:
- not specified
- Dose descriptor:
- LC100
- Effect level:
- >= 82 - <= 260 mg/L air
- Based on:
- test mat.
- Remarks on result:
- other: mortality occurred within 13-70 min
- Interpretation of results:
- other: STOT-SE 3, H336
- Conclusions:
- When rats were exposed to vapour concentrations of 82,000-260,000 mg/m3 (ca. 20,000-62,000 ppm), mortality occurred within 13-70 minutes, animals showing anaesthesia, lethargy, ataxia, and terminal convulsion. Exposure to 11,000 mg/m3 (ca. 2600 ppm), for 6 hours, induced only minor symptoms (lethargy in 3 hours).
Based on the narcotic effects observed in this study at high concentration classification of methylcyclohexane according to Regulation (EC) No 1272/2008 as STOT-SE 3 (narcotic effects) is fully justified.
Since it was judged in the SIDS INITIAL ASSESSMENT PROFILE for the Methyl-Ethylcyclohexane Category that the read across from methyl- to ethylcyclohexane is plausible and can be proven by the similarity in structure and physicochemical properties, it is assumed that ethylcyclohexane will behave in a similar manner with respect to acute inhalation toxicity. Therefore ethylcyclohexane will be classified as STOT-SE 3 (narcotic effects) too. - Executive summary:
When rats were exposed to vapour concentrations of 82,000-260,000 mg/m3 (ca. 20,000-62,000 ppm), mortality occurred within 13-70 minutes, animals showing anaesthesia, lethargy, ataxia, and terminal convulsion. Exposure to 11,000 mg/m3 (ca. 2600 ppm), for 6 hours, induced only minor symptoms (lethargy in 3 hours).
Based on the narcotic effects observed in this study at high concentration classification of methylcyclohexane according to Regulation (EC) No 1272/2008 as STOT-SE 3 (narcotic effects) is fully justified.
Since it was judged in the SIDS INITIAL ASSESSMENT PROFILE for the Methyl-Ethylcyclohexane Category that the read across from methyl- to ethylcyclohexane is plausible and can be proven by the similarity in structure and physicochemical properties, it is assumed that ethylcyclohexane will behave in a similar manner with respect to acute inhalation toxicity. Therefore ethylcyclohexane will be classified as STOT-SE 3 (narcotic effects) too.
- Endpoint:
- acute toxicity: inhalation
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- weight of evidence
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- abstract
- Justification for type of information:
- Justification for Read Across from methycyclohexane:
The methyl-ethylcyclohexane category has been agreed by OECD member countries and was evaluated and justified in the OECD SIDS INITIAL ASSESSMENT PROFILE (available at: http://webnet.oecd.org/HPV/UI/handler.axd?id=05fc63c8-e637-45aa-b3ff-6c19545e6c76).
Citation from "SIDS INITIAL ASSESSMENT PROFILE-Methylï½¥Ethylcyclohexane Category":
"Category rationale(citation):
The methyl-ethylcyclohexane category consists of two chemicals which are methylcyclohexane and ethylcyclohexane. Both of the chemicals have a cyclohexane-ring as a basic molecular structure, and either a methyl functional group (-CH3) or an ethyl functional group (-CH2-CH3) is directly connected to this ring. Both chemicals are liquid at standard temperature and pressure. Based on the close similarity of molecular structures, all physical-chemical properties are similar.
There are a number of unifying considerations, which justify the inclusion of these two chemicals within the same category. These include:
1. Similarity of molecular structure and functional group:
These chemicals have a similar structure which is a direct connection of either methyl functional group (-CH3) or an ethyl functional group (-CH2-CH3) to the cyclohexane ring.
2. Similarity of physical-chemical properties:
All physiccal-chemical properties, especially water solubility, vapour pressure and log Kow are similar.
3. Similarity in health effects:
Toxicokinetic properties are similar.
Target organs of repeated dose toxicity are the liver and kidney for both chemicals.
Both chemicals show negative results of genotoxicity.
4. Similarity of environmental fate and distribution:
Both chemicals show the same or similar tendency in their environmental distribution, and biodegradation, which leads to the same behavior for these chemicals in the real environment.
5. Similarity of eco-toxicity:
Aquatic toxicity to fish (acute), daphnid (acute) and algae (acute and chronic) for both chemicals are very similar" - Reason / purpose for cross-reference:
- read-across source
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- Acute inhalation toxicity study in mice
- GLP compliance:
- not specified
- Test type:
- other: not specified
- Limit test:
- no
- Species:
- mouse
- Strain:
- not specified
- Sex:
- not specified
- Route of administration:
- inhalation: vapour
- Type of inhalation exposure:
- not specified
- Vehicle:
- not specified
- Duration of exposure:
- 2 h
- Sex:
- not specified
- Dose descriptor:
- LC50
- Effect level:
- 10 172 ppm
- Based on:
- test mat.
- Exp. duration:
- 2 h
- Sex:
- not specified
- Dose descriptor:
- LC50
- Effect level:
- 41.5 mg/L air
- Based on:
- test mat.
- Exp. duration:
- 2 h
- Interpretation of results:
- GHS criteria not met
- Conclusions:
- In mice, a 2-hour LC50 of 41,500 mg/m3 (ca. 10,000 ppm) is reported. No detailed study description is given.
Since it was judged in the SIDS INITIAL ASSESSMENT PROFILE for the Methyl-Ethylcyclohexane Category that the read across from methyl- to ethylcyclohexane is plausible and can be proven by the similarity in structure and physicochemical properties, it is assumed that ethylcyclohexane will behave in a similar manner with respect to acute inhalation toxicity. - Executive summary:
In mice, a 2-hour LC50 of 41,500 mg/m3 (ca. 10,000 ppm) is reported. No detailed study description is given.
Since it was judged in the SIDS INITIAL ASSESSMENT PROFILE for the Methyl-Ethylcyclohexane Category that the read across from methyl- to ethylcyclohexane is plausible and can be proven by the similarity in structure and physicochemical properties, it is assumed that ethylcyclohexane will behave in a similar manner with respect to acute inhalation toxicity.
- Endpoint:
- acute toxicity: inhalation
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- weight of evidence
- Study period:
- 1943
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- study well documented, meets generally accepted scientific principles, acceptable for assessment
- Justification for type of information:
- Justification for Read Across from methycyclohexane:
The methyl-ethylcyclohexane category has been agreed by OECD member countries and was evaluated and justified in the OECD SIDS INITIAL ASSESSMENT PROFILE (available at: http://webnet.oecd.org/HPV/UI/handler.axd?id=05fc63c8-e637-45aa-b3ff-6c19545e6c76).
Citation from "SIDS INITIAL ASSESSMENT PROFILE-Methylï½¥Ethylcyclohexane Category":
"Category rationale
The methyl-ethylcyclohexane category consists of two chemicals which are methylcyclohexane and ethylcyclohexane. Both of the chemicals have a cyclohexane-ring as a basic molecular structure, and either a methyl functional group (-CH3) or an ethyl functional group (-CH2-CH3) is directly connected to this ring. Both chemicals are liquid at standard temperature and pressure. Based on the close similarity of molecular structures, all physical-chemical properties are similar.
There are a number of unifying considerations, which justify the inclusion of these two chemicals within the same category. These include:
1. Similarity of molecular structure and functional group
These chemicals have a similar structure which is a direct connection of either methyl functional group (-CH3) or an ethyl functional group (-CH2-CH3) to the cyclohexane ring.
2. Similarity of physical-chemical properties
All physiccal-chemical properties, especially water solubility, vapour pressure and log Kow are similar.
3. Similarity in health effects
Toxicokinetic properties are similar.
Target organs of repeated dose toxicity are the liver and kidney for both chemicals.
Both chemicals show negative results of genotoxicity.
4. Similarity of environmental fate and distribution
Both chemicals show the same or similar tendency in their environmental distribution, and biodegradation, which leads to the same behavior for these chemicals in the real environment.
5. Similarity of eco-toxicity
Aquatic toxicity to fish (acute), daphnid (acute) and algae (acute and chronic) for both chemicals are very similar" - Reason / purpose for cross-reference:
- read-across source
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- Determination of the minimum lethal concentration after repeated inhalation exposure
- GLP compliance:
- not specified
- Test type:
- other: minimum lethal concentration
- Limit test:
- no
- Key result
- Sex:
- not specified
- Dose descriptor:
- LC100
- Effect level:
- 59.9 mg/L air
- Based on:
- test mat.
- Exp. duration:
- 70 min
- Key result
- Sex:
- not specified
- Dose descriptor:
- other: mortality
- Effect level:
- 28.75 - 39.55 mg/L air
- Based on:
- test mat.
- Exp. duration:
- 6 h
- Key result
- Sex:
- not specified
- Dose descriptor:
- other: minimum narcotic concentration
- Effect level:
- 21.9 mg/L air
- Based on:
- test mat.
- Exp. duration:
- 6 h
- Interpretation of results:
- other: STOT-SE 3 H336 May cause drowsiness and dizziness
- Conclusions:
- In this rabbit study, all the animals died at 59.9 mg/L within 70 min after exposure initiation. LC50 was considered as between 39.6 and 59.9 mg/L. Signs of toxicity at 59.9 mg/L (70 min exposure) included severe convulsions, rapid narcosis, labored breathing, salivation, and conjunctival congestion.
- Executive summary:
In this rabbit study, all the animals died at 59.9 mg/L within 70 min after exposure initiation. LC50 was considered as between 39.6 and 59.9 mg/L. Signs of toxicity at 59.9 mg/L (70 min exposure) included severe convulsions, rapid narcosis, labored breathing, salivation, and conjunctival congestion.
In this study, mortality after single and repeated exposure occurred only at high to very high concentrations of methylcyclohexane, which are above the currently valid LC50 ranges used for classification. Therefore, the study results do not fulfil the classification criteria for acute toxicity by inhalation. Based on the narcotic effects consistently observed at high concentrations in this and further studies (Weight of Evidence), methylcyclohexane fulfils the classification criteria for Specific target organ toxicity-single exposure (STOT-SE) Category 3 (narcotic effects).
Referenceopen allclose all
Endpoint conclusion
- Endpoint conclusion:
- adverse effect observed
- Dose descriptor:
- LC50
- Value:
- 39 600 mg/m³ air
Acute toxicity: via dermal route
Link to relevant study records
- Endpoint:
- acute toxicity: dermal
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 1992-01-28 - 1992-04-07
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 402 (Acute Dermal Toxicity)
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Test type:
- fixed dose procedure
- Limit test:
- yes
- Specific details on test material used for the study:
- SRLD or Lot I.D. Number: 7482-9A
Physical State and Appearance: Colorless liquid - Species:
- rat
- Strain:
- other: CD(SD)BR VAF/PlusT
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- Body Weight Range at Dosing (grams): Males = 230 - 254 Females =190 - 202
Housing:
All animals were individually housed in suspended, stainless-steel, mesh cages.
Environmental Conditions:
A photoperiod of 12 hours light from 6 a.m. to 6 p.m. Room temperature was maintained at
71-75*F. Relative humidity was maintained at 45-48%.
Diet and-Water:
ad libitum - Type of coverage:
- occlusive
- Vehicle:
- unchanged (no vehicle)
- Details on dermal exposure:
- The hair was removed from an area of the dorsal skin with an electric clipper. A single dose of the material was placed in contact with the skin using a fiber pad and an occlusive wrap to hold the test material in place for 24 hours. At the end of the exposure period, the test material was removed with running water.
- Duration of exposure:
- 24 hours
- Doses:
- 2000 mg/kg bw
- No. of animals per sex per dose:
- 5 of each sex per dose group
- Control animals:
- no
- Details on study design:
- Clinical Observations:
Animals were observed during the exposure period (Day 0) and once each workday thereafter for the duration of the experiment (a total of 14 calendar days). Observation included, but was not limited to: examination of the hair, skin, eyes, motor activity, feces, and urine. Animals were checked for mortality on weekend days.
Body Weight Determinations:
Body weights were collected on the day of dosing and one and two weeks after dosing.
Necropsy:
All animals were necropsied at the completion of the 14-day observation period. - Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- > 2 000 mg/kg bw
- Based on:
- test mat.
- Mortality:
- none
- Clinical signs:
- other: No treatment-related abnormal clinical signs were evident at any time during the 14-day observation period.
- Gross pathology:
- No treatment-related changes or signs of organ toxicity were evident at necropsy. In the absence of significant gross organ lesions, no tissue was
collected for histological examination. - Interpretation of results:
- GHS criteria not met
- Conclusions:
- The acute dermal LD50 for this test material was greater than 2000 mg/kg for both sexes.
- Executive summary:
A limit dose of 2000 mg/kg was applied to the skin after the hair was removed with an electric clipper. An occlusive wrap was used to hold the test material against the skin for a period of 24 hours, and at the end of exposure, residual test material was washed off with running water.
No treatment-related abnormal clinical signs were evident at any time during the 14-day observation period. On the last day of the observation period, a small wound with a scab was noted on the shoulder of a single male (Rat 745). Since this animal had appeared clinically normal from the day of dosing to Day 13, this wound was not considered related to administration of the test material. No treatment-related changes or signs of organ toxicity were evident at necropsy. In the absence of significant gross organ lesions, no tissue was collected for histological examination. Based on weight gain and survival rate, there was no evidence of percutaneous absorption. The acute dermal LD50 for this test material was greater than 2000 mg/kg for both sexes.
Reference
Summary Table
DOSE (mg/kg) |
NUMBER OF RATS DOSED (M,F) |
NUMBER OF DEATHS (M,F) |
TIME OF DEATH |
WEIGHT GAIN* (M,F) |
|
1WEEK |
2WEEKS |
||||
2000 |
5,5 |
0,0 |
-------- |
5 +, 5+ |
5 +, 5+ |
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- LD50
- Value:
- 2 000 mg/kg bw
- Quality of whole database:
- The reported study is guideline and GLP compleant.
Additional information
Justification for classification or non-classification
Acute oral toxicity:
The respective criteria are not met. Therefore ethylcyclohexane has not to be classified for acute oral toxicity.
Acute dermal toxicity:
The respective criteria are not met. Therefore ethylcyclohexane has not to be classified for acute dermal toxicity.
Acute inhalation toxicity:
Based on the narcotic effects observed in the available studies for methylcyclohexane at high concentrations classification of methylcyclohexane according to Regulation (EC) No 1272/2008 as STOT-SE 3 (narcotic effects) is fully justified.
By applying the read-across approach ethylcyclohexane will be classified as STOT-SE 3 (narcotic effects) too.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.