Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 221-877-8 | CAS number: 3266-23-7
Toxicological Summary
Administrative data
Workers - Hazard via inhalation route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DMEL (Derived Minimum Effect Level)
- Value:
- 3 mg/m³
- Most sensitive endpoint:
- carcinogenicity
DNEL related information
- Overall assessment factor (AF):
- 500
- Modified dose descriptor starting point:
- T25
Acute/short term exposure
- Hazard assessment conclusion:
- DMEL (Derived Minimum Effect Level)
- Value:
- 30 mg/m³
- Most sensitive endpoint:
- repeated dose toxicity
DNEL related information
- Overall assessment factor (AF):
- 500
- Modified dose descriptor starting point:
- LOAEC
Local effects
Long term exposure
- Hazard assessment conclusion:
- DMEL (Derived Minimum Effect Level)
- Value:
- 3 mg/m³
- Most sensitive endpoint:
- carcinogenicity
DNEL related information
- Overall assessment factor (AF):
- 500
- Dose descriptor:
- T25
Acute/short term exposure
- Hazard assessment conclusion:
- DMEL (Derived Minimum Effect Level)
- Value:
- 30 mg/m³
- Most sensitive endpoint:
- repeated dose toxicity
DNEL related information
- Overall assessment factor (AF):
- 500
- Dose descriptor starting point:
- LOAEC
Workers - Hazard via dermal route
Systemic effects
Acute/short term exposure
DNEL related information
Workers - Hazard for the eyes
Additional information - workers
The most critical effect is tumorigenicity as demonstrated by a study with the structural homologue 1,2-epoxybutane (CAS 106 -88 -7; Butylene oxide-1.2). Moreover, 2.3-epoxybutane may contain up to 20 % of 1.2-epoxybutane. Therefore, the legal classification for this material is also employed for the 2.3 -isomer.
In a long-term inhalation study in rats 1.2-epoxybutane has caused nasal and lung tumors in rats. The following tumor incidences were obtained in the males:
| Dose | Nasal adenoma | Lung adenoma plus carcinoma |
| 0 ppm | 0 | 0 |
| 200 ppm | 0 | 8.9% |
| 400 ppm | 24.2% | 17.6% |
At 400 ppm there was a markedly decreased survival in male rats. In females, a low tumor response was seen only at 400 ppm. For the nasal tumors in males a T25 of 413 ppm is obtained. For lung tumors in males a T25 of 568 ppm (calculated from the top dose) or 562 ppm (calculated from the lower dose ) is obtained. A linear extrapolation from a T25 of 500 ppm would indicate a numerical risk of 1:2000 at 1 ppm. However, the real risk is assumed to be lower due to a likelyhood for non-linear elements in the dose response relation at lower doses (as it has been shown for propylene oxide). 1 ppm (= 3 mg/m3) can therefore serve as a preliminary DMEL for epoxybutane ( - both isomers). This value should also be protective from local effects including nasal tumors.
No dermal DNELs/DMELs are derived, because there is no dermal exposure unless in accidental cases.
Due to the structural similarities, the same conclusions can be drawn for 2,3 -epoxybutane.
General Population - Hazard via inhalation route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DMEL (Derived Minimum Effect Level)
- Value:
- 0.5 mg/m³
- Most sensitive endpoint:
- carcinogenicity
DNEL related information
- Overall assessment factor (AF):
- 3 000
Acute/short term exposure
- Hazard assessment conclusion:
- DMEL (Derived Minimum Effect Level)
- Value:
- 5 mg/m³
- Most sensitive endpoint:
- repeated dose toxicity
DNEL related information
- Overall assessment factor (AF):
- 300
- Modified dose descriptor starting point:
- LOAEC
Local effects
Long term exposure
- Hazard assessment conclusion:
- DMEL (Derived Minimum Effect Level)
- Value:
- 0.5 mg/m³
- Most sensitive endpoint:
- carcinogenicity
DNEL related information
- Overall assessment factor (AF):
- 3 000
- Dose descriptor:
- T25
Acute/short term exposure
- Hazard assessment conclusion:
- DMEL (Derived Minimum Effect Level)
- Value:
- 5 mg/m³
- Most sensitive endpoint:
- repeated dose toxicity
DNEL related information
- Overall assessment factor (AF):
- 300
- Dose descriptor starting point:
- LOAEC
General Population - Hazard via dermal route
Systemic effects
Acute/short term exposure
DNEL related information
General Population - Hazard via oral route
Systemic effects
Acute/short term exposure
DNEL related information
General Population - Hazard for the eyes
Additional information - General Population
For the general population, the chronic worker DMEL is devided by 6. No dermal or oral exposure is expected.
Due to the structural similarities, the same conclusions can be drawn for 2,3 -epoxybutane.
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.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
