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EC number: 270-790-1
CAS number: 68478-10-4
A complex combination of hydrocarbons obtained by the distillation of debenzenized light steam-cracked naphtha. It consists predominantly of cyclic olefinic and aromatic hydrocarbons having carbon numbers predominantly in the range of C8 through C16 and boiling in the range of approximately 130°C to 300°C (226°F to 572°F).
Dicyclopentadiene is of slight - moderate acute toxicity by the oral and inhalation routes (oral LD50 590 mg/kg, inhalation 4 hour LC50 1972 mg/m3) and is practically
non-toxic by the dermal route (dermal LD50 > 2000 mg/kg). The NOAEC for irregular breathing, stereotypic behaviour in rats and mice has been reported to be 248.74 mg/m3 (Bushy Run, 1981).
toxicity : oral
In what is considered to be the key
study (Safepharm, 1989a), groups of fasted Sprague Dawley rats were
dosed by gavage at dose levels of 500, 794, 1260 or 2000 mg/kg of resin
grade dicyclopentadiene with a purity of 75% dicylcopentadiene and observed
daily for 14 days after dosing. Signs
of toxicity (including lethargy and decreased respiratory rate) were
seen after dosing with 1260 or 2000 mg/kg bw, with ptosis and occasional
signs of ataxia seen 4 hours after dosing with 2000 mg/kg bw. All
rats dosed with 1260 or 2000 mg/kg bw died one or two days after dosing.
lungs, dark liver and sloughing of the non-glandular gastric epithelium
were seen in decedents. The LD50 was calculated to be 590 mg/kg bw
(male/female); 512 mg/kg for males and 676 mg/kg/bw for females.
supporting studies by Litton Bionetics (1976c) the oral LD50 in the
Sprague Dawley rat was 449 mg/kg (male/female); 520 mg/kg for males and
378 mg/kg for females. Slightly lower LD50 values were found in Swiss
Webster mice: 220 mg/kg (male/female); 190 mg/kg for males and 250 mg/kg
for females. Although the mouse acute oral LD50 values are slightly
lower than the rat, the mouse acute toxicity studies have a Klimisch
code of 2 while the key study in the rat was asssigned a Klimisch code
of 1. Furthermore, OECD guideline 401 states that although
several mammalian test species may be used, the rat is the preferred
toxicity : inhalation
near-guideline studies assessing the acute inhalation toxicity of
dicyclopentadiene exposure in rats and mice for 6 hours have been
reported (Bushy Run, 1981). These studies were conducted to obtain a
definitive LC50 value that was not confounded by fracturing of the
dicyclopentadiene (previous publications have given conflicting LC50
values that might have been caused by loss of dicyclopentadiene via
fracturing). Chamber concentrations of dicyclopentadiene and
cyclopentadiene were monitored by gas chromatography/flame ionization
detection with a detection limit for both chemicals of 0.05 ppm;
cyclopentadiene was below the detection limit in both studies.
the rat study, groups of Fischer 344 rats were exposed for 6 hours to
vapours containing 46, 130, 260 or 557 ppm and then observed daily for
up to 14 days. At
557 ppm, all females were found dead on the day after exposure and all
males died within 24 hours of exposure. At 260 ppm, two males were found
dead on the day after exposure, all females survived. Clinical signs
included loss of righting reflex, impaired gait, stereotypic behaviour,
laboured breathing, nasal discharge and convulsions. The 6 hour LC50 was
284 ppm for males and 353 ppm for females, equivalent to 1723 mg/m3
(male/female). Conversion of this result using Haber's rule (n=3) gives
a 4 hour LC50 equivalent of 1972 mg/m3 for males and females.
for irregular breathing and stereotypic behaviour was 46 ppm (248.74
the mouse study, groups of B6C3F1 mice were exposed for 6 hours to the
same vapour concentrations of dicyclopentadiene and then observed daily
for up to 14 days. At
557 ppm, all mice died within 24 hours of exposure. At
260 ppm, all males were found dead on the day after exposure and all
females died during exposure or within 24 hours. At 130 ppm, 2 males and
3 females died within 24 hours of exposure. There were no deaths at 46
ppm. Clinical signs included loss of righting reflex, impaired gait,
stereotypic behaviour, laboured breathing, clear nasal discharge, loss
of coordination and convulsions prior to death. The 6 hour LC50 was 143
ppm for males and 126 ppm for females, equivalent to 738.5 mg/m3
(male/female). The NOAEC
for irregular breathing and stereotypic behaviour was 46 ppm (248.74
studies assessed the acute inhalation toxicity of dicyclopentadiene
exposure for 4 hours in rats, mice, dogs and rabbits (Kinkead et al,
LC50 in the male albino rat was 359.4 ppm (1943 mg/m3) and in the female
was 385.2 ppm (2083 mg/m3). These
values are consistent with the LC50 equivalent of 1972 mg/m3 for males
and female rats calculated using Haber's rule from the Bushy Run, (1981)
the male mouse the 4 hour LC50 was 145.5 ppm (787 mg/m3) and for the
male rabbit was 771 ppm (4171mg/m3). For
the female dog, the 4 hour LC50 was between 458 and 773 ppm (2473-4174
coordination and convulsions were seen in all species, especially prior
to death and eye and nose irritation, lachrymation and tremors were
observed in the dog study.
toxicity : dermal
In what is considered to be
the key study (Safepharm 1989b), the acute dermal toxicity of resin
grade dicyclopentadiene with a purity of 75% dicylcopentadiene
was assessed in a group of 5 male and 5 female rats. 2000 mg/kg
bodyweight of the chemical was applied to an area of clipped, intact
dorsal skin and held in place with an occlusive dressing. Animals were
observed at 1 and 4 hours after dosing and then daily for 14 days.
Clinical signs present in all animals on day 1 included vocalisation for
up to 30 minutes, hunched posture, lethargy, piloerection, erythema and
oedema. All animals showed signs of eschar by
day 3 which persisted until days 10 or 12 but all treatment sites
appeared normal by the end of the study. The acute dermal LD50 of
dicyclopentadiene 75% to the rat was greater than 2000 mg/kg bodyweight.
two rabbit studies, the acute dermal LD50 of undiluted dicyclopentadiene
was 4460 mg/kg bw (Smyth et al, 1962) and 6720 mg/kg bw (Smyth et al,
observations of systemic toxicity were reported.
No relevant information
is harmful by the oral route with an LD50 value of 590 mg/kg which
justifies classification Category
4 (H302) under CLP (Harmonised classification).
the data presented, the calculated 4 hr LC50 of 1972 mg/m3 justifies
classification as Category 2 classification under CLP
(Fatal if inhaled).
is of low acute toxicity by the dermal route with an LD50 greater than
2000 mg/kg and therefore does not warrant classification under CLP
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