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EC number: 203-313-2
CAS number: 105-60-2
No valid animal data available, classification as an irritant on all relevant routes of exposure based on human experience.
No valid animal data is available for the test substance with regard to
skin and eye irritation.
The most valuable animal skin irritation study is a range finding study
of a skin sensitization test in which 0.4ml of a 75% test
substance-solution were applied to the clipped skin of guinea pigs
(Springborn, 1991). 24h following a 6h occlusive incubation period mild
signs of irritation were observed which decreased after a further 24h
observation period. Therefore mild skin irritation can not be ruled out,
though due to significant deviations to the OECD guideline 404 no
classification according to EU- or GHS-standards can be performed.
In an acute dermal assay application of 2000mg/kg bw on an undefined
area of rat skin did not result in local signs of irritation (Bayer,
No valid study to approximate the potential to irritate mucosa is
In an inhalation study with mice (Alarie test, Industrial Health
Foundation, 1990), pulmonary irritation of CAP was studied by exposing
groups of 4 guinea pigs for 30 min/day on 5 consecutive days to 3
aerosol concentrations (0.003, 0.01 and 0.03 mg/l). There was no change
in respiratory frequency (f) or amplitude (AP). Following inhalation
exposure the breathing patterns remained unaltered (i.e., no sensory or
pulmonary irritation) and there was no evidence of airway constriction.
In a further inhalation study (Dupont, 1997), groups of 4 male mice were
exposed for 30 min to saturated vapors of CAP (0.0094 mg/l) and
evaluated for sensory irritation. A decrease in respiratory frequency of
8% was observed, which is generally considered within the expected range
for control mice exposed to air in this system. However, during this
exposure there was some evidence of slight sensory irritation observed
in 1 of 3 mice.
In man the solid substance and concentrated solutions were reported to
be local irritants (e.g. Brief, 1971; Antoniev & Gerasimow, 1971) and in
some reports high concentrations of the dust were irritant to mucous
membranes (e.g. Tuma et al., 1981; Reinhold et al. 1998).
Eye irritation, burning nostril, irritation of the throat and coughing
were observed in most of the healthy human volunteers exposed to
artificially generated the test substance vapors (10-104 ppm,and
In low atmospheric concentrations the test substance is existent as a
vapor, whereas in higher concentrations increased aerosol formation
occurs due to the low vapor pressure.
In order to study the chemosensory effects on the conjunctiva or nasal
mucosa at low concentrations below the MAK value, Ziegler et al. (2008)
exposed 20 healthy subjects (10 male, 10 female) for 6 h exposures to
vaporous the test substance in the concentrations of 0, 0.15, 0.5 and 5
mg/m3. Indications for an increases in blink frequency, nasal resistance
and irritation were reported in the highest test concentration (5
mg/m3), although not to statistically significant degree and therefore
not adverse. Also the subjective indications of symptoms increased
statistically insignificant with rising levels of exposure. Only odor
nuisance was significantly more pronounced than at zero exposure (P <
0.001) even in the low concentration range.
Triebig et al. (2016) examined symptoms and objective effects which
occur on the mucous membranes of the eyes and the upper respiratory
tract of human volunteers after inhalation exposure to caprolactam. A
total of 52 healthy volunteers were assessed. Chamber exposures were
random to caprolactam concentrations of 0, 0.05, 0.5 and 5 mg/m3 for six
hours on four consecutive days. There were no significant differences
comparing the results before and after the daily exposures. Statistical
analysis yielded no evidence of concentration-response relationships.
Evaluation of olfactory symptoms showed that the duration of stay in the
chamber and not the test substance concentration was decisive for the
perception of “impure air”. Personality factors had no significant
influence on the reported symptoms. Exposure to the test substance
concentrations of 5 mg/m3 at maximum for six hours at for consequtive
days did not cause chemosensory effects on the upper respiratory tract
or eyes of healthy volunteers. Therefore, the concentration of 5 mg/m3
corresponds to the NOEC (No Observed Effect Concentration).
Kelman (1986) reported minor complaints of sensory irritation and
peeling and/or fissuring of the skin in a group of eight workers exposed
to the test substance fume/dust levels of 68 mg/m3 (range 22-168 mg/m3)
for 9 months to 13 years. At mean concentration of 61 mg/m3 test
substance vapor workmen in spinning rooms reported dry, splitting nose
and lips, noose bleed and upper respiratory catarrh (Hohensee, 1951).
The maximum allowable concentration at the workplace (German MAK value)
is defined as the maximum concentration of a chemical substance in the
workplace air which generally does not have known adverse effects on the
health of the employee and does not cause unreasonable annoyance even
when the person is repeatedly exposed during long periods, usually for 8
hours daily but assuming on average a 40-hour working week (DFG, 2005).
For the test substance the MAK value was identified as 5 mg/m3,
corresponding with the U.S. Threshold Limit Value (TLV; ACGIH, 2004).
Both values were in principle established on the basis of its known
irritant effects on man (mucosal, skin or chemosensory irritation).
No valid animal data available, classification as an irritant on all
relevant routes of exposure based on human experience.
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.
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