Registration Dossier
Registration Dossier
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EC number: 234-126-4 | CAS number: 10544-72-6
Toxicological Summary
Administrative data
Workers - Hazard via inhalation route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- other toxicological threshold
- Value:
- 0.955 mg/m³
- Most sensitive endpoint:
- repeated dose toxicity
- Route of original study:
- By inhalation
DNEL related information
- DNEL derivation method:
- ECHA REACH Guidance
- Modified dose descriptor starting point:
- other: not applicable
- Explanation for the modification of the dose descriptor starting point:
- No route-to-route extrapolation needed.
- Justification:
- Not applicable
- Justification:
- Not applicable, IOEL (SCOEL, 2014) set for 8-hour occupational exposure
- Justification:
- Not applicable, IOEL (SCOEL, 2014) set based on human data
- Justification:
- Not applicable, IOEL (SCOEL, 2014)set based on human data
- Justification:
- Not applicable, IOEL (SCOEL, 2014) set based on human data
- Justification:
- Not applicable
- Justification:
- Not applicable
Acute/short term exposure
- Hazard assessment conclusion:
- other toxicological threshold
- Value:
- 1.91 mg/m³
- Most sensitive endpoint:
- acute toxicity
- Route of original study:
- By inhalation
DNEL related information
- DNEL derivation method:
- ECHA REACH Guidance
- Modified dose descriptor starting point:
- other: not applicable
- Explanation for the modification of the dose descriptor starting point:
- No route-to-route extrapolation needed
- Justification:
- Not applicable
- Justification:
- Not applicable, IOEL (SCOEL, 2014) set for 15-min occupational exposure
- Justification:
- Not applicable, IOEL (SCOEL, 2014) set based on human data
- Justification:
- Not applicable, IOEL (SCOEL, 2014) set based on human data
- Justification:
- Not applicable
- Justification:
- Not applicable
Local effects
Long term exposure
- Hazard assessment conclusion:
- other toxicological threshold
- Value:
- 0.95 mg/m³
- Most sensitive endpoint:
- repeated dose toxicity
DNEL related information
- DNEL derivation method:
- ECHA REACH Guidance
- Dose descriptor:
- other: not applicable
- Justification:
- Not applicable
- Justification:
- Not applicable, IOEL (SCOEL, 2014) set for 8-hour occupational exposure
- Justification:
- Not applicable, IOEL (SCOEL, 2014) set based on human data
- Justification:
- Not applicable, IOEL (SCOEL, 2014) set based on human data
- Justification:
- Not applicable, IOEL (SCOEL, 2014) set based on human data
- Justification:
- Not applicable
- Justification:
- Not applicable
Acute/short term exposure
- Hazard assessment conclusion:
- other toxicological threshold
- Value:
- 1.91 mg/m³
DNEL related information
- DNEL derivation method:
- ECHA REACH Guidance
- Dose descriptor starting point:
- other: not applicable
- Justification:
- Not applicable
- Justification:
- Not applicable, IOEL (SCOEL, 2014) set for 15-min occupational exposure
- Justification:
- Not applicable, IOEL (SCOEL, 2014) set based on human data
- Justification:
- Not applicable, IOEL (SCOEL, 2014) set based on human data
- Justification:
- Not applicable
- Justification:
- Not applicable
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:
- high hazard (no threshold derived)
- Most sensitive endpoint:
- skin irritation/corrosion
Acute/short term exposure
- Hazard assessment conclusion:
- high hazard (no threshold derived)
- Most sensitive endpoint:
- skin irritation/corrosion
Workers - Hazard for the eyes
Local effects
- Hazard assessment conclusion:
- high hazard (no threshold derived)
Additional information - workers
For the monomer of dinitrogen tetraoxide, nitrogen dioxide, an International Occupational Exposure Limit (IOEL) has been set by the Scientific Committee on Occupational Exposure Limits (8 -h TWA of 0.96 mg/m3and 15 -min STEL of 1.91 mg/m3) in 2014.Dinitrogen tetraoxide exists in equilibrium with nitrogen dioxide, with ca. 25% present in the form of NO2at 25 °C. At greater dilution, e.g. with air, the amount of NO2is greater. Therefore it would seem inevitable that toxicological studies performed with either of the two substances would share a common mechanism. Therefore read-across from NO2to N2O4considered to be justified.
In accordance with Chapter R.8 of the ECHA Guidance on information requirements and chemical safety assessment, a registrant is allowed to use an IOEL as a DNEL for the same exposure route and duration, unless new scientific information that he obtained in fulfilling his obligations under REACH does not support the use of the IOEL for this purpose. Based on the study with rats of Han and co-workers (2013), in which genotoxic effects were observed in several tissues following inhalation exposure to the monomer of dinitrogen tetraoxide, nitrogen dioxide, classification of dinitrogen tetraoxide as Mutagenic Cat. 1B, H340, is proposed by the registrant. This study was not taken into account in the SCOEL (2014) evaluation.
However, the use of the limit values set by the SCOEL (2014) for nitrogen dioxide as DNELs is still considered to be justified by the registrant, based on the following considerations:
1) the limit values are derived based on the human data set and are considered to be sufficient to protect against the critical effects of nitrogen dioxide, which are local effects in the deep respiratory tract, for both acute and repeated exposure.
2) The genotoxic effects observed in the study of Han et al. (2013) occurred at concentrations several times higher than the limit values for both acute and repeated exposure set by SCOEL (2014). Therefore the limit values set by the SCOEL (2014) are considered to be sufficient to protect against these effects and will therefore be used in the risk assessment.
Dinitrogen tetraoxide is a dimer of nitrogen dioxide. Therefore the respective 8-h TWA and 15-min STEL values for nitrogen dioxide were converted to 0.25 and 0.5 ppm, respectively, for dinitrogen tetraoxide based on molar ratio, which corresponds to 0.955 and 1.91 mg/m3. These values will be used in the risk assessment as DNELs for repeated and acute exposure, respectively.
Dinitrogen tetraoxide is classified as corrosive and causes predominantly local effects at the port of entry. The substance is a gas and thus respiratory route of exposure is considered to be the most relevant. Systemic effects are considered to be secondary to local effects. The set IOEL is considered to to be sufficient to protect against local and systemic effects.
The substance is classified as corrosive and as such considered to represent a high hazard for local effects on skin and eyes. However, as the substance is a gas, respiratory route of exposure is considered to be the most relevant and no direct skin or eye exposure is envisaged.
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
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
Not used by the general population.
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.
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