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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Workers - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
14.5 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:
721 mg/m³
Modified dose descriptor starting point:
NOAEC
Value:
362.3 mg/m³
Explanation for the modification of the dose descriptor starting point:

One key study (Ulrich, 1982; Klimisch score = 2) was available for 2-methylpropane-2-thiol. In this 90-day inhalation study, the repeated dose toxicity of 2-methylpropane-2-thiol was investigated in Sprague Dawley rats. The NOAEC was identified to be 0.721 mg/L (196 ppm or 721 mg/m³) based on the absence of systemic toxicity effects at the highest concentration tested (0.721 mg/L or 196 ppm).

Step 1) Relevant dose-descriptor

NOAEC6h/rat: 0.721 mg/L

Step 2) Modification of starting point 

Conversion for units:0.721 mg/L x 1000 = 721 mg/m³

Correction of exposure duration in study 

(6 hrs/day, 5 days/week) to default worker exposure (8 hrs/day, 5 days/ week)

Correction for activity driven differences of respiratory volumes in workers compared to workers in rest

6.7 mg/m³ /10 Corrected NOAEC = 362.3 mg/m³ (= 721 x 6/8 x 6.7/10)

AF for dose response relationship:
1
AF for differences in duration of exposure:
2
Justification:
Default sub-chronic to chronic
AF for interspecies differences (allometric scaling):
1
AF for other interspecies differences:
2.5
Justification:
Default systemic effects
AF for intraspecies differences:
5
Justification:
Default workers
AF for the quality of the whole database:
1
Justification:
Default
AF for remaining uncertainties:
1
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
18.6 mg/m³
Most sensitive endpoint:
repeated dose toxicity
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
10
Dose descriptor:
NOAEC
Value:
370 mg/m³
AF for dose response relationship:
1
AF for differences in duration of exposure:
2
Justification:
For sub-chronic to chronic
AF for interspecies differences (allometric scaling):
1
AF for other interspecies differences:
1
Justification:
For local effects
AF for intraspecies differences:
5
Justification:
For workers
AF for the quality of the whole database:
1
AF for remaining uncertainties:
1
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Workers - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
2.06 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:
721 mg/m³
Modified dose descriptor starting point:
NOAEL
Value:
205.5 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:

No key dermal repeat dose toxicity data was available for 2 -methylpropane-2-thiol. One key oral study (MHLW, 2006; Klimisch score = 2) of 2 -methylpropane-2-thiol has been performed but not used in the derivation of this DNEL because a reliable 90 -day inhalation study was available. Therefore, in the absence of oral data, key inhalation data (Ulrich, 1982; Klimisch score = 2) was used by performing a route-to-route extrapolation. The NOAEC used was 0.721 mg/L (196 ppm or 721 mg/m3).

Step 1) Relevant dose-descriptor

NOAEC6h/rat: 0.721 mg/L

Step 2) Modification of starting point

Conversion for units:

0.721 mg/L x 1000 = 721 mg/m3

Correction of rat inhalation NOAEC to rat dermal NOAEL – correction for respiratory volume and for difference in absorption rates

NOAELrat: 274 mg/kg bw/day

(= 721 x 0.38 x 1)

Assumption: Based on ECHA guidance (Chapter R.8) no default factor was applied for differences in absorption in rats and humans and therefore absorption was assumed to be 100% via the dermal and inhalation route

Correction of exposure duration in study

(6 hrs/day, 5 days/week) to default worker exposure (8 hrs/day, 5 days/ week)

Corrected NOAEL = 205.5 mg/kg bw/day

(=274 x 6/8)

AF for dose response relationship:
1
AF for differences in duration of exposure:
2
Justification:
For sub-chronic to chronic
AF for interspecies differences (allometric scaling):
4
Justification:
Rat
AF for other interspecies differences:
2.5
Justification:
For systemic effect
AF for intraspecies differences:
5
Justification:
For worker population
AF for the quality of the whole database:
1
AF for remaining uncertainties:
1
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
medium hazard (no threshold derived)
Most sensitive endpoint:
sensitisation (skin)
Acute/short term exposure
Hazard assessment conclusion:
medium hazard (no threshold derived)
Most sensitive endpoint:
sensitisation (skin)

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:
no hazard identified

Additional information - workers

General Population - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
2.57 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):
50
Dose descriptor starting point:
NOAEC
Value:
721 mg/m³
Modified dose descriptor starting point:
NOAEC
Value:
128.7 mg/m³
Explanation for the modification of the dose descriptor starting point:

One key study (Ulrich, 1982; Klimisch score = 2) was available for 2-methylpropane-2-thiol. In this 90-day inhalation study, the repeated dose toxicity of 2-methylpropane-2-thiol was investigated in Sprague Dawley rats. The NOAEC was identified to be 0.721 mg/L (196 ppm or 721 mg/) based on the absence of systemic toxicity effects at the highest concentration tested (0.721 mg/L or 196 ppm).

Step 1) Relevant dose-descriptor

NOAEC 6h/rat: 0.721 mg/L

Step 2) Modification of starting point 

Conversion for units:0.721 mg/L x 1000 = 721 mg/

Correction of exposure duration in study 

(6 hrs/day, 5 days/week) to default general population exposure (24 hrs/day, 7 days/ week)Corrected NOAEC = 128.7 mg/(= 721 x 6/24 x 5/7)

AF for dose response relationship:
1
AF for differences in duration of exposure:
2
Justification:
Sub-chronic to chronic
AF for interspecies differences (allometric scaling):
1
AF for other interspecies differences:
2.5
Justification:
For systemic effect
AF for intraspecies differences:
10
Justification:
For general population
AF for the quality of the whole database:
1
AF for remaining uncertainties:
1
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
3.3 mg/m³
Most sensitive endpoint:
repeated dose toxicity
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
20
Dose descriptor:
NOAEC
Value:
370 mg/m³
AF for dose response relationship:
1
AF for differences in duration of exposure:
2
Justification:
For sub-chronic to chronic
AF for interspecies differences (allometric scaling):
1
AF for other interspecies differences:
1
Justification:
For local effects
AF for intraspecies differences:
10
Justification:
For general population
AF for the quality of the whole database:
1
AF for remaining uncertainties:
1
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:
DNEL (Derived No Effect Level)
Value:
3 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):
200
Dose descriptor starting point:
NOAEC
Value:
721 mg/m³
Modified dose descriptor starting point:
NOAEL
Value:
592 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:

A 90-day inhalation repeated dose toxicity study (Ulrich, 1982; Klimisch score = 2) has been performed and is used as the starting point for this DNEL. The NOAEC was identified to be 0.721 mg/L (196 ppm or 721 mg/m³) based on the absence of systemic toxicity effects at the highest concentration tested (0.721 mg/L or 196 ppm).

The following correction was made to the NOAEC (inhaled): Correction respiratory volume rat (24 hour) = 1.15 m³/kg bw. Correction for dosing frequency: 5 days/7 days. Therefore, the corrected NOAEL for repeat-dose systemic effects via the dermal/oral route is: 721*1.15*(5/7) = 592 mg/kg bw/day.

AF for dose response relationship:
1
Justification:
Default
AF for differences in duration of exposure:
2
Justification:
Default, subchronic to chronic
AF for interspecies differences (allometric scaling):
4
Justification:
Default
AF for other interspecies differences:
2.5
Justification:
Default
AF for intraspecies differences:
10
Justification:
Default, general population
AF for the quality of the whole database:
1
Justification:
Default, the NOAEL is from a reliable study on 2-methylpropane-2-thiol.
AF for remaining uncertainties:
1
Justification:
Default
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
medium hazard (no threshold derived)
Most sensitive endpoint:
sensitisation (skin)
Acute/short term exposure
Hazard assessment conclusion:
medium hazard (no threshold derived)
Most sensitive endpoint:
sensitisation (skin)

General Population - Hazard via oral route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
83.3 µg/kg bw/day
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
600
Dose descriptor starting point:
NOAEL
Value:
50 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:

A 28-day oral repeated dose toxicity study (MHLW, 2006; Klimisch score = 1) of 2-methylpropane-2-thiol has been performed and is used in the derivation of this DNEL. The NOAEL used was 50 mg/kg bw/day. No modification of the dose descriptor starting point is required.

AF for dose response relationship:
1
Justification:
Default
AF for differences in duration of exposure:
6
Justification:
Default, subacute to chronic
AF for interspecies differences (allometric scaling):
4
Justification:
Default, Rat to human
AF for other interspecies differences:
2.5
Justification:
Default
AF for intraspecies differences:
10
Justification:
Default, general population
AF for the quality of the whole database:
1
Justification:
Default, the NOAEL is from a reliable study on 2-methylpropane-2-thiol.
AF for remaining uncertainties:
1
Justification:
Default
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