Registration Dossier
Registration Dossier
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EC number: 213-668-5 | CAS number: 999-97-3
Toxicological Summary
Administrative data
Workers - Hazard via inhalation route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 53 mg/m³
- Most sensitive endpoint:
- repeated dose toxicity
- Route of original study:
- By inhalation
DNEL related information
- DNEL derivation method:
- ECHA REACH Guidance
- Overall assessment factor (AF):
- 25
- Dose descriptor starting point:
- NOAEC
- Value:
- 2 640 mg/m³
- Modified dose descriptor starting point:
- NOAEC
- Value:
- 1 327 mg/m³
- Explanation for the modification of the dose descriptor starting point:
The DNEL for long term systemic effects via the inhalation route is determined on the basis of the 90-day inhalation toxicity study conducted on the parent substance 1,1,1,3,3,3-hexamethyldisilazane in which a NOAEC of 400 ppm (2640 mg/m³) was established (Dow Corning Corporation, 2007).
The following correction was made to the NOAEC (inhalation): Correction for experimental exposure duration (6 h/d to 8 h/d), Correction for respiratory volume (worker): 6.7 m³/10 m³. Therefore the corrected NOAEC for repeated-dose systemic effects via the inhalation route is: 2640 mg/m³*(6 h/ 8 h) *(6.7 m³/10 m³) = 1327 mg/m ³.
- AF for dose response relationship:
- 1
- Justification:
- Default (a clear NOAEC was established)
- AF for differences in duration of exposure:
- 2
- Justification:
- Default (sub-chronic to chronic)
- AF for interspecies differences (allometric scaling):
- 1
- Justification:
- Default (inhaled rat to inhaled human)
- AF for other interspecies differences:
- 2.5
- Justification:
- ECHA default
- AF for intraspecies differences:
- 5
- Justification:
- ECHA default
- AF for the quality of the whole database:
- 1
- Justification:
- Default (guideline study)
- AF for remaining uncertainties:
- 1
- Justification:
- No remaining uncertainties
Acute/short term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 106 mg/m³
- Most sensitive endpoint:
- repeated dose toxicity
- Route of original study:
- By inhalation
DNEL related information
- DNEL derivation method:
- ECHA REACH Guidance
- Overall assessment factor (AF):
- 12.5
- DNEL extrapolated from long term DNEL
- Explanation for the modification of the dose descriptor starting point:
The DNEL for short-term systemic effects via the inhalation route is based on the DNEL for long-term systemic effects via the inhalation route except that the default assessment factor for differences in duration of exposure is omitted.
Local effects
Long term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 133 mg/m³
- Most sensitive endpoint:
- irritation (respiratory tract)
DNEL related information
- DNEL derivation method:
- other: EU OEL
- Overall assessment factor (AF):
- 1
- Dose descriptor:
- other: OEL
Acute/short term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 341 mg/m³
- Most sensitive endpoint:
- irritation (respiratory tract)
DNEL related information
- DNEL derivation method:
- other: EU STEL
- Overall assessment factor (AF):
- 1
- Dose descriptor starting point:
- other: EU STEL
Workers - Hazard via dermal route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 7.5 mg/kg bw/day
- Most sensitive endpoint:
- repeated dose toxicity
- Route of original study:
- By inhalation
DNEL related information
- DNEL derivation method:
- ECHA REACH Guidance
- Overall assessment factor (AF):
- 100
- Dose descriptor starting point:
- NOAEC
- Value:
- 2 640 mg/m³
- Modified dose descriptor starting point:
- NOAEL
- Value:
- 752 mg/kg bw/day
- Explanation for the modification of the dose descriptor starting point:
The DNEL for long term systemic effects via the dermal route is determined on the basis of the 90-day inhalation toxicity study conducted on the parent substance 1,1,1,3,3,3-hexamethyldisilazane, in which a NOAEC of 400 ppm (2640 mg/m³) was established (Dow Corning Corporation, 2007).
The following correction was made to the NOAEC (inhaled): Correction respiratory volume rat (8 hour) = 0.38 m³/kg bw. Correction for exposure duration: 6 h/8 h (6 hours exposure in rats to 8 hours exposure in workers). Therefore the corrected NOAEL for repeat-dose systemic effects via the dermal route is: 2640*(6/8)*0.38 = 752 mg/kg bw/day
- AF for dose response relationship:
- 1
- Justification:
- Default
- AF for differences in duration of exposure:
- 2
- Justification:
- Default (sub-chronic to chronic)
- AF for interspecies differences (allometric scaling):
- 4
- Justification:
- Default (inhaled rat to dermal human)
- AF for other interspecies differences:
- 2.5
- Justification:
- Default
- AF for intraspecies differences:
- 5
- Justification:
- Default
- AF for the quality of the whole database:
- 1
- Justification:
- Default (guideline study)
- AF for remaining uncertainties:
- 1
- Justification:
- No remaining uncertainties
Acute/short term exposure
- Hazard assessment conclusion:
- medium hazard (no threshold derived)
- Most sensitive endpoint:
- acute toxicity
- Route of original study:
- Dermal
DNEL related information
- DNEL derivation method:
- ECHA REACH Guidance
Local effects
Long term exposure
- Hazard assessment conclusion:
- low hazard (no threshold derived)
- Most sensitive endpoint:
- skin irritation/corrosion
Acute/short term exposure
- Hazard assessment conclusion:
- low hazard (no threshold derived)
Workers - Hazard for the eyes
Local effects
- Hazard assessment conclusion:
- low hazard (no threshold derived)
Additional information - workers
General Population - Hazard via inhalation route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- no hazard identified
Acute/short term exposure
- Hazard assessment conclusion:
- no hazard identified
DNEL related information
Local effects
Long term exposure
- Hazard assessment conclusion:
- no hazard identified
DNEL related information
- AF for intraspecies differences:
- 2
Acute/short term exposure
- Hazard assessment conclusion:
- no hazard identified
DNEL related information
General Population - Hazard via dermal route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- no hazard identified
Acute/short term exposure
- Hazard assessment conclusion:
- no hazard identified
DNEL related information
Local effects
Long term exposure
- Hazard assessment conclusion:
- no hazard identified
Acute/short term exposure
- Hazard assessment conclusion:
- no hazard identified
General Population - Hazard via oral route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- no hazard identified
Acute/short term exposure
- Hazard assessment conclusion:
- no hazard identified
DNEL related information
General Population - Hazard for the eyes
Local effects
- Hazard assessment conclusion:
- no hazard identified
Additional information - General Population
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