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EC number: 265-198-5 | CAS number: 64742-94-5 A complex combination of hydrocarbons obtained from distillation of aromatic streams. It consists predominantly of aromatic hydrocarbons having carbon numbers predominantly in the range of C9 through C16 and boiling in the range of approximately 165°C to 290°C (330°F to 554°F).
- 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
Dicyclopentadiene is considered to be irritating to skin and the respiratory system and slightly irritating to eyes.
Key value for chemical safety assessment
Skin irritation / corrosion
Endpoint conclusion
- Endpoint conclusion:
- adverse effect observed (irritating)
Eye irritation
Endpoint conclusion
- Endpoint conclusion:
- adverse effect observed (irritating)
Respiratory irritation
Endpoint conclusion
- Endpoint conclusion:
- adverse effect observed (irritating)
Additional information
Non human information
Skin
In what is considered to be the key skin irritation study in New Zealand White rabbits (Safepharm, 1989c) 0.5 mL of dicyclopentadiene 75% was applied to an area of clipped, intact skin under a semi-occlusive dressing for 4 hours. Animals were observed at 1 and 4 hours after removal of the patch and then daily for 7 days. Well-defined erythema and slight to severe oedema was present at all sites and for all rabbits at 24, 48 and 72 hour observation times. On day 7, no oedema was noted but there were signs of possible hyperkeratinisation. No other adverse dermal reactions were noted during the study. The overall mean scores (24, 48 and 72 h) were 2 for erythema and 2.3 for oedema; dicyclopentadiene 75% was a therefore considered to be a moderate irritant of rabbit skin.
In an older supporting study. New Zealandwhite rabbits were used to assess skin irritation following a 24 hour, uncovered, application of 0.01 mL undiluted dicyclopentadiene (Smyth 1962). The overall irritation score (on a scale of 1 -10) was 5 and confirmed that undiluted dicyclopentadiene was moderately irritating to rabbit skin.
Eye
In what is considered to be the key eye irritation study in New Zealand White rabbits (Safepharm 1989d) 0.1 mL dicyclopentadiene 75% was instilled into the conjunctival sac and the eyes were scored for irritation responses at 1, 24, 48 and 72 hours and at 7 days after instillation. Moderate irritation was present at 1 hour in all 3 rabbit eyes; iridial inflammation and conjunctival irritation were present in all cases and corneal dulling was present in 2. However, signs of irritation regressed to minimal in 2 eyes at 24 hours. Although corneal redness persisted in 1 animal at 72 hours, all effects were fully reversible within 7 days.
In a supporting study (Litton Bionetics, 1976a) using undiluted dicyclopentadiene, initial conjunctival irritation was present in 7 out of 9 rabbits but had recovered by day 3. Undiluted dicyclopentadiene was practically non-irritating at 24, 48 and 72 hours in this study.
Respiratory
Whilst there are no specific studies assessing respiratory irritation, laboured/ irregular breathing, nasal discharge and haemorrhagic lungs post mortem were evident in acute inhalation exposures of rats and mice (Bushy Run, 1981) and dose-dependent eye irritation was observed in a variety of species during acute inhalation exposures to neat dicyclopentadiene vapour (Kinkead et al, 1971).
Human information
Very
little information has been reported on the irritation effects of
dicyclopentadiene in humans. However, in a study in volunteers to
determine the human sensory response to dicyclopentadiene vapour, 2
subjects inhaled analysed concentrations of 1 ppm and 5.5 ppm for 30
minutes (Kinkead et al, 1971). Both concentrations caused sporadic eye
and throat irritation and one subject could taste dicyclopentadiene for
1 hr after the 5.5 ppm exposure. Human exposure to vapours of
dicyclopentadiene is considered likely to result in respiratory and
ocular irritation. The literature was reviewed (Amoore et al, 1983) to
provide quantitative data on the odour thresholds of 214 chemicals
including dicyclopentadiene. Data on the volatility, solubility,
ionisation and water-air distribution ratio at 25ºC were collected and a
safe dilution factor and an odour safety factor were calculated. For
dicyclopentadiene the threshold limit value was 5 ppm v/v, the
volatility at 25ºC was 3600 ppm v/v, the air odour threshold was
0.0057±1.9 ppm. The
calculated safe dilution factor was 720 and the odour safety factor was
870. On the basis of these results, dicyclopentadiene was placed in
odour safety class A (i. e. more than 90% of distracted persons
perceived warning of TLV concentration in the air).
Effects on skin irritation/corrosion: moderately irritating
Effects on eye irritation: slightly irritating
Effects on respiratory irritation: irritating
Justification for classification or non-classification
The animal studies of both undiluted dicyclopentadiene and dicyclopentadiene 75% demonstrate moderate skin irritation and justify the classification of Category 2 (Irritant) with the hazard statement" H315 causes skin irritation" under CLP.
In the key study of eye irritation, dicyclopentadiene 75% was non-irritant but undiluted dicyclopentadiene showed slight eye irritation in a supporting study. Maintenance of the classification as Category 2 "H319 Causes serious eye irritation" under CLP is proposed.
The observations of respiratory tract irritation in animals and humans means that dicyclopentadiene warrants classification as Category 3 for transient target organ toxicity under STOT-RE under CLP.
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