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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