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EC number: 217-496-1
CAS number: 1873-88-7
The key study for acute oral toxicity reports an LD50 value of >2000
mg/kg bw which was determined in a reliable study with the registered
substance, carried out in accordance with OECD TG 425 and in compliance
with GLP (RCC 2008).
The acute inhalation study is read across from octamethyltrisiloxane
(L3, CAS 107-51-7). The animals were exposed to vapour and an LC50 value
of >22.6 mg/l (analytical) was determined in a reliable study conducted
according to an appropriate test protocol, and in compliance with GLP
(Dow Corning 2004). In addition, a study was conducted according to OECD
403 and in compliance with GLP for the read-across substance
1,1,3,3-tetramethyldisiloxane (H2 -L2, CAS 3277-26-7). The animals were
exposure to vapour and an LC50 value >5.8 mg/l (measured) was determined
(Dow Corning Corporation, 1994).
In accordance with Column 2 of REACH Annex VIII, the acute toxicity
study via the dermal route (required in Section 8.5.2) does not need to
be conducted as reliable data via the oral and inhalation routes are
The key study for acute oral toxicity reported an LD50 value
of >2000 mg/kg bw in rat, in a reliable and GLP compliant study (RCC
2008). There were no mortalities during the study period. Slightly to
moderately ruffled fur was noted in all animals from the 1- or 5- hour
reading up to test day 2 or 3, persisting in one animal through test day
7. Slight to marked sedation was recorded in all animals from the 2-, 3-
or 5-hour observation up to 5 hours post-dose or test days 2 or 3. Two
animals showed slightly poor coordination on test day 2 only, while two
other animals showed slight to markedly or slightly to moderately poor
coordination from 5 hours post-dose until test day 2. Hunched posture
was observed in four animals at the 1-hour reading and persisted through
the 5-hour evaluation in one animal and through test day 2 in three
animals. Ventral recumbency was noted in one animal on test day 2. The
body weight of animals was within normal range. No macroscopic findings
were recorded at necropsy.
The key study for acute inhalation was read across from
octamethyltrisiloxane (L3, CAS 107-51-7). The study was conducted
according to an appropriate OECD/EU test guideline, and in compliance
with GLP. The reported LC50 value is >22.6 mg/l (Dow Corning
2004). There were no mortalities, no clinical signs or macroscopic
abnormalities reported at necropsy. Furthermore, all body weight gains
were considered normal for both sexes.
Read across was also included for acute inhalation from the related
substance 1,1,3,3-tetramethyldisiloxane (H2 -L2, CAS 3277-26-7).
The study was conducted according to an appropriate OECD/EU test
guideline, and in compliance with GLP. A well reported study, conducted
according to generally accepted scientific standards and in accordance
with GLP, found no toxicity when male and female rats were exposed for 4
h to a measured atmosphere containing 5.8 mg/l (vapour) of the test
material. The LC50 would exceed this value. There were no
treatment-related abnormalities reported. Clinical signs of rapid
respiration and salivation were recorded. There were no mortalities (Dow
Corning Corporation, 1994).
Based on the available information, no classification is necessary for
acute toxicity in accordance with Regulation (EC) No 1272/2008.
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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