tert-butyl acrylate

Toxicological Summary

Workers - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

16 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):

10

Dose descriptor starting point:

NOAEC

Value:

319 mg/m³

Modified dose descriptor starting point:

NOAEC

Value:

160.3 mg/m³

Explanation for the modification of the dose descriptor starting point:

Starting point is a NOAEC of 319 mg/m3. This inhalatory rat NOAEC was converted into inhalatory worker NOAEC by correction for exposure period (6h for rat versus 8h for worker) and respiratory rate based on activity (6.7 m3 for normal light activity versus 10 m3 for worker activity): 319 * (6/8) * (6.7/10) = 160.3 mg/m3

AF for dose response relationship:

1

Justification:

In accordance with ECHA Guidance on information requirements and chemical safety assessment – Chapter 8: Characterisation of dose [concentration]-response for human health, for the dose-response relationship, consideration should be given to the uncertainties in the dose descriptor (NOAEL, benchmark dose…) as the surrogate for the true no-adverse-effect-level (NAEL). In this case the starting point for the DNEL calculation is a NOAEC, derived from a study which is of good quality and without uncertainties. Therefore the default assessment factor, as a standard procedure, is 1.

AF for differences in duration of exposure:

2

Justification:

In accordance with ECHA Guidance on information requirements and chemical safety assessment – Chapter 8: Characterisation of dose [concentration]-response for human health, a factor allowing for differences in the experimental exposure duration and the duration of exposure for the worker and scenario under consideration needs to be considered taking into account that a) in general the experimental NOAEL will decrease with increasing exposure times and b) other and more serious adverse effects may appear with increasing exposure times. Consequently, to end up with the most conservative DNEL for repeated dose toxicity, chronic exposure is the ‘worst case’. So, as only a sub-chronic toxicity study is available, default assessment factor of 2 is to be applied, as a standard procedure.

AF for interspecies differences (allometric scaling):

1

Justification:

In accordance with ECHA Guidance on information requirements and chemical safety assessment – Chapter 8: Characterisation of dose [concentration]-response for human health, as long as route-to-route extrapolation is not needed, allometric scaling should not be applied in cases where doses in experimental animal studies are expressed as concentrations (e.g. in mg/m3 air, ppm in diet, or mg/L in the drinking water) as these are assumed to be already scaled according to the allometric principle, since ventilation rate and food intake directly depend on the basal metabolic rate. In this case the NOAEC is expressed as concentration (mg/m3), therefore a factor for allometric scaling is not needed. In ECETOC Derivation of Assessment Factors for Human Health Risk Assessment – Technical Report No. 86 and ECETOC Guidance on Assessment Factors to Derive a DNEL – Technical Report No. 110, a similar approach is followed. The rationale here is that allometric scaling should not be applied because in humans inhalation rate is 7-fold lower compared to mice according to the slower metabolic rate and thereby the allometric species difference is already implicitly taken into account.

AF for other interspecies differences:

1

Justification:

In accordance with ECETOC Derivation of Assessment Factors for Human Health Risk Assessment – Technical Report No. 86 and ECETOC Guidance on Assessment Factors to Derive a DNEL – Technical Report No. 110, potential differences in biological sensitivity between species are largely accounted for in the default assessment factor proposed for intraspecies variability.

AF for intraspecies differences:

5

Justification:

In accordance with ECHA Guidance on information requirements and chemical safety assessment – Chapter 8: Characterisation of dose [concentration]-response for human health, a default assessment factor for the general population is based on the distributions of human data for various toxicokinetic and toxicodynamic parameters. This results in recommended default assessment factor of 10 for the general population. As the worker population is more homogeneous (i.e. younger, healthier, protected from exposures), a default assessment factor of 5 is recommended.

AF for the quality of the whole database:

1

Justification:

In accordance with ECHA Guidance on information requirements and chemical safety assessment – Chapter 8: Characterization of dose [concentration]-response for human health, the evaluation of the total toxicological database should include an assessment whether the available information as a whole meets the tonnage driven data requirements necessary to fulfil the REACH requirements, or whether there are data gaps (completeness of the database). Furthermore, the hazard data should be assessed for the reliability and consistency across different studies and endpoints and taking into account the quality of the testing method, size and power of the study design, biological plausibility, dose-response relationships and statistical association (adequacy of the database). When taking into account the standard information requirements and the completeness and consistency of the database the default assessment factor of 1, to be applied for good/standard quality of the database, is recommended.

AF for remaining uncertainties:

1

Justification:

In accordance with ECHA Guidance on information requirements and chemical safety assessment – Chapter 8: Characterisation of dose [concentration]-response for human health, a factor allowing for remaining uncertainties should be used where necessary. As the approach used for DNEL derivation is conservative, no further assessment factors are required

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:

11 mg/m³

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

DNEL derivation method:

other: adapted from Scientific Expert Group on Occupational Exposure Limits (SCOEL)

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:

no hazard identified

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:

low hazard (no threshold derived)

Most sensitive endpoint:

skin irritation/corrosion

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:

medium hazard (no threshold derived)

General Population - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

8 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):

20

Dose descriptor starting point:

NOAEC

Value:

319 mg/m³

Modified dose descriptor starting point:

NOAEC

Value:

160.3 mg/m³

Explanation for the modification of the dose descriptor starting point:

Starting point is a NOAEC of 319 mg/m3. This inhalatory rat NOAEC was converted into inhalatory worker NOAEC by correction for exposure period (6h for rat versus 8h for worker) and respiratory rate based on activity (6.7 m3 for normal light activity versus 10 m3 for worker activity): 319 * (6/8) * (6.7/10) = 160.3 mg/m3

AF for dose response relationship:

1

Justification:

In accordance with ECHA Guidance on information requirements and chemical safety assessment – Chapter 8: Characterisation of dose [concentration]-response for human health, for the dose-response relationship, consideration should be given to the uncertainties in the dose descriptor (NOAEL, benchmark dose…) as the surrogate for the true no-adverse-effect-level (NAEL). In this case the starting point for the DNEL calculation is a NOAEC, derived from a study which is of good quality and without uncertainties. Therefore the default assessment factor, as a standard procedure, is 1.

AF for differences in duration of exposure:

2

Justification:

In accordance with ECHA Guidance on information requirements and chemical safety assessment – Chapter 8: Characterisation of dose [concentration]-response for human health, a factor allowing for differences in the experimental exposure duration and the duration of exposure for the worker and scenario under consideration needs to be considered taking into account that a) in general the experimental NOAEL will decrease with increasing exposure times and b) other and more serious adverse effects may appear with increasing exposure times. Consequently, to end up with the most conservative DNEL for repeated dose toxicity, chronic exposure is the ‘worst case’. So, as only a sub-chronic toxicity study is available, default assessment factor of 2 is to be applied, as a standard procedure.

AF for interspecies differences (allometric scaling):

1

Justification:

In accordance with ECHA Guidance on information requirements and chemical safety assessment – Chapter 8: Characterisation of dose [concentration]-response for human health, as long as route-to-route extrapolation is not needed, allometric scaling should not be applied in cases where doses in experimental animal studies are expressed as concentrations (e.g. in mg/m3 air, ppm in diet, or mg/L in the drinking water) as these are assumed to be already scaled according to the allometric principle, since ventilation rate and food intake directly depend on the basal metabolic rate. In this case the NOAEC is expressed as concentration (mg/m3), therefore a factor for allometric scaling is not needed. In ECETOC Derivation of Assessment Factors for Human Health Risk Assessment – Technical Report No. 86 and ECETOC Guidance on Assessment Factors to Derive a DNEL – Technical Report No. 110, a similar approach is followed. The rationale here is that allometric scaling should not be applied because in humans inhalation rate is 7-fold lower compared to mice according to the slower metabolic rate and thereby the allometric species difference is already implicitly taken into account.

AF for other interspecies differences:

1

Justification:

In accordance with ECETOC Derivation of Assessment Factors for Human Health Risk Assessment – Technical Report No. 86 and ECETOC Guidance on Assessment Factors to Derive a DNEL – Technical Report No. 110, potential differences in biological sensitivity between species are largely accounted for in the default assessment factor proposed for intraspecies variability.

AF for intraspecies differences:

10

Justification:

In accordance with ECHA Guidance on information requirements and chemical safety assessment – Chapter 8: Characterisation of dose [concentration]-response for human health, a default assessment factor for the general population is based on the distributions of human data for various toxicokinetic and toxicodynamic parameters. This results in recommended default assessment factor of 10 for the general population.

AF for the quality of the whole database:

1

Justification:

In accordance with ECHA Guidance on information requirements and chemical safety assessment – Chapter 8: Characterization of dose [concentration]-response for human health, the evaluation of the total toxicological database should include an assessment whether the available information as a whole meets the tonnage driven data requirements necessary to fulfil the REACH requirements, or whether there are data gaps (completeness of the database). Furthermore, the hazard data should be assessed for the reliability and consistency across different studies and endpoints and taking into account the quality of the testing method, size and power of the study design, biological plausibility, dose-response relationships and statistical association (adequacy of the database). When taking into account the standard information requirements and the completeness and consistency of the database the default assessment factor of 1, to be applied for good/standard quality of the database, is recommended.

AF for remaining uncertainties:

1

Justification:

In accordance with ECHA Guidance on information requirements and chemical safety assessment – Chapter 8: Characterisation of dose [concentration]-response for human health, a factor allowing for remaining uncertainties should be used where necessary. As the approach used for DNEL derivation is conservative, no further assessment factors are required

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:

1.27 mg/m³

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

DNEL derivation method:

other: derived from Scientific Expert Group on Occupational Exposure Limits (SCOEL)

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