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EC number: 203-806-2 | CAS number: 110-82-7
- 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
Cyclohexane is considered to be a skin irritant based on results from animal experiments. It is slightly irritating to the eyes in animal experiments but not to an extent that would require classification.
Key value for chemical safety assessment
Skin irritation / corrosion
Link to relevant study records
- Endpoint:
- skin irritation: in vivo
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Guideline study, GLP status unclear, acceptable for assessment
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)
- Principles of method if other than guideline:
- Cyclohexane was applied to shaved rabbit skin and erythema and oedema recorded (using Draize criteria) at 1, 24, 48, and 72 hr after removal of the patch. Observations continued thereafter every 2 days until dermal responses had resolved in at least one rabbit.
- GLP compliance:
- not specified
- Species:
- rabbit
- Strain:
- New Zealand White
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Source: Proefstations voor Veeteelt (Merelbeke, Belgium)
- Age at study initiation: 9-24 weeks
- Weight at study initiation: 2.75-5.2 kg
- Housing: individual mesh wire bottom cages
- Diet: Conventional Laboratory diet ad libitum
- Water: Tap-water ad libitum
- Acclimatisation period: At least 7 days
- Normal housing conditions - Type of coverage:
- occlusive
- Preparation of test site:
- shaved
- Vehicle:
- unchanged (no vehicle)
- Controls:
- no
- Amount / concentration applied:
- 0.5 mL
- Duration of treatment / exposure:
- 4 hours, occluded
- Observation period:
- Animals examined for signs of erythema and oedema formation at 1, 24, 48 and 72 hr after removal of the test patch
- Number of animals:
- 5 or 6 (not specified)
- Irritation parameter:
- erythema score
- Basis:
- mean
- Remarks:
- for all animals, all timepoints
- Time point:
- 24/48/72 h
- Score:
- 1.93
- Remarks on result:
- other: time course information not available
- Irritation parameter:
- erythema score
- Basis:
- mean
- Remarks:
- maximum erythema score (Smax)
- Time point:
- other: 119 h (time of Smax)
- Score:
- 2.56
- Irritation parameter:
- edema score
- Basis:
- mean
- Remarks:
- for all animals, all timepoints
- Time point:
- 24/48/72 h
- Score:
- 0
- Interpretation of results:
- not irritating
- Conclusions:
- Cyclohexane caused erythema (overall mean 1.93) when applied to shaved rabbit skin under occlusion for 4 hr. The magnitude of the response was below the threshold for classification.
- Executive summary:
The skin irritation potential of cyclohexane toward shaved rabbit skin was evaluated according to Annex V of directive 67/548 EEC. The sample (0.5 mL) was applied under occlusion for 4 hr with an area of untreated skin serving as control. The overall mean score for erythema (all animals over all times points) was 1.93; no oedema was reported. The results indicate that cyclohexane is not irritating to rabbit skin.
Reference
Endpoint conclusion
- Endpoint conclusion:
- adverse effect observed (irritating)
Eye irritation
Link to relevant study records
- Endpoint:
- eye irritation, other
- Remarks:
- In Vivo
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: GLP status unknown, near guideline study, available as unpublished report, restrictions in design and/or reporting but otherwise adequate for assessment.
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 405 (Acute Eye Irritation / Corrosion)
- Deviations:
- yes
- Remarks:
- Deviation did not impact the scientific validity of the study.
- GLP compliance:
- not specified
- Species:
- rabbit
- Strain:
- not specified
- Details on test animals or tissues and environmental conditions:
- Not reported
- Vehicle:
- not specified
- Controls:
- no
- Amount / concentration applied:
- Not reported
- Duration of treatment / exposure:
- Not reported
- Observation period (in vivo):
- 7 days
- Number of animals or in vitro replicates:
- 6
- Irritation parameter:
- overall irritation score
- Remarks:
- cornea
- Basis:
- mean
- Time point:
- other: 1 h
- Score:
- 2
- Reversibility:
- fully reversible within: 24 h
- Irritation parameter:
- overall irritation score
- Remarks:
- iris
- Basis:
- mean
- Time point:
- other: 1 h
- Score:
- 0.8
- Reversibility:
- fully reversible within: 24 h
- Irritation parameter:
- overall irritation score
- Remarks:
- conjunctivae
- Basis:
- mean
- Time point:
- other: 1 h
- Score:
- 2
- Reversibility:
- fully reversible within: 24 h
- Irritation parameter:
- overall irritation score
- Basis:
- other: total (cornea, iris and conjuctivae)
- Time point:
- other: 1 h
- Score:
- 3.7
- Reversibility:
- fully reversible within: 24 h
- Interpretation of results:
- slightly irritating
- Conclusions:
- Slight eye irritation effects were present 1 hour after instillation but had resolved within 24 hours.
- Executive summary:
Slight eye irritation effects were present 1 hour after instillation but had resolved within 24 hours.
Reference
The report states that corneal opacity (involving up to 25% of the cornea) was noted in one rabbit and iritis in another 1 hr post-instillation however the rapid reversibility of these responses (both fully resolved by 24 hr) suggests possible over-interpretation. Conjunctival redness was also noted in 5 rabbits with conjunctival chemosis in one, however responses again cleared within 24 hours.
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed (not irritating)
Respiratory irritation
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed (not irritating)
Additional information
Skin
Non-human information
There are two skin irritation studies using rabbits reported (HLA, 1982e; Jacobs and Martens, 1987), both performed in accordance with EEC Directive 83/467/EEC. The first study, conducted under a semi-occlusive dressing, gave a primary irritation score of zero 24 h and 72 h. The second study, under a semi-occlusive dressing, gave a mean erythema score of 1.93 calculated over the 24 h and 72 h post-application period. In this study the erythematous reaction reached maximum severity at 5 days post-application with a gradual increase in dermal reaction for a further 144 h observation time. Overall, it was concluded (RAR, 2004) that the irritation reactions were significant and still present at the end of the study.
In addition, a 14 -day repeated dermal application study in rabbits on uncovered skin has been reported (Treon et al., 1943a). An initial erythematous response, gradually progressing to skin hardening, fissuring and bleeding with continued application was reported (RAR, 2004), with healing of the lesions within one week once application of cyclohexane had ceased.
Human information
Very little information has been reported on the irritation effects of cyclohexane in humans. No eye irritation was reported in a human volunteer study (Lammers et al, 2009) where the maximum exposure concentration was 250 ppm (860 mg/m3).
The following information was cited in the RAR (2004) from an UK HSE review of cyclohexane. Application of undiluted liquid cyclohexane to human skin for 1 hour produced erythema and weal formation.
Eye
Non-human information
Washed and unwashed primary eye irritation studies in rabbits are available (HLA, 1982f; 1982g). In the unwashed study, at one hour post instillation, corneal opacity, involving up to 25% of the cornea, was noted in one rabbit and iritis was noted in another rabbit. Conjunctival redness was noted in five rabbits with conjunctival chemosis in one rabbit. All ocular lesions had cleared within 24 hours and no conjunctival discharge was noted in any of the six animals.
Human information
Very little information has been reported on the irritation effects of cyclohexane in humans. In a TNO study (Lammers et al, 2009), human volunteers exposed to 250 ppm (860 mg/m3) of cyclohexane complained of irritation of the eyes more frequently than those treated with 25 ppm (86 mg/m3).
Respiratory tract
Non-human information
Acute inhalation exposure to cyclohexane at a nominal concentration of 32, 880 mg/m3 of air did not appear to produce upper airway irritation in mice (Phillips Petroleum Company, 1982i). In this study, cyclohexane (vapour) was administered to 2 groups of 4 cd-1 male mice for 2 periods of 1 minute separated by 10 minutes. The only effect noted was a slight decrease (11.2% and 5.8%) in the respiratory rate of only one animal (out of four) in the two experiments. This animal also exhibited very slight respiratory pauses which may have been due to upper airway irritation.
Human information
Justification for selection of skin irritation / corrosion endpoint:
Liquid cyclohexane is moderately irritating to rabbit skin, and may also cause defatting.
Justification for selection of eye irritation endpoint:
Liquid cyclohexane is slightly irritating to rabbit eye, but not to an extent that would lead to classification.
Effects on skin irritation/corrosion: moderately irritating
Justification for classification or non-classification
In relation to skin irritation, although the animal studies gave results slight below the limits of classification, the RAR (2004) concluded that it had been demonstrated that the irritant properties of cyclohexane were delayed and persisted until the end of observation period (16 days).
Since defatting properties are also expected, it was concluded that cyclohexane be classified under CLP as Category 2 H315.
Liquid cyclohexane is slightly irritant to the eyes in animal experiments, but not to the extent which warrants any classification. Although cyclohexane vapour exhibited slight respiratory irritant properties in mice, these effects were slight and insufficient to warrant classification.
There is no evidence of any significant eye or respiratory tract irritation in humans which would warrant classification
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