ETHYLENE OXIDE‡

Chemical Identification
CAS # 75-21-8
Formula
 

C₂H₄O

Synonyms
 

dimethylene oxide; 1,2-epoxyethane; oxirane; ETO

Physical Properties
Physical description Colorless gas or liquid (below 51°F) with an ether-like odor.
Boiling point 51°F Molecular weight 44.1
Freezing point/melting point -171°F Vapor pressure 1.46 atm
Flash point -20°F (liquid) Vapor density 1.49
Specific gravity 0.82 (liquid at 50°F) Ionization potential 10.56 eV
Lower explosive limit (LEL) 3.0% Upper explosive limit (UEL) 100%
NFPA health rating 3 NFPA fire rating 4
NFPA reactivity rating 3 NFPA special instruction
Vapor hazard ratio (VHR)
Historical exceedance percentage
Target organs
Monitoring Methods Used by OSHA
Analyte code (IMIS no.) 1190
Sampling group
Sampler/Sampling media HBr coated petroleum-based CSC (100/50 mg) [SKC 226-178]
Sampling time*
 

240 min

Sampling volume (TWA)*
 
 

12 L

Sampling flow rate (TWA)*
 
 

0.05 L/min

Sampling volume (STEL/Peak/C)*
 
 

0.75 L

Sampling flow rate (STEL/Peak/C)*
 
 

0.05 L/min

Analytical method instruments GC-ECD
Method reference OSHA 1010v.2 (fully validated)
Notes
 
 

 

Special requirements
 
 

 

* All sampling instructions above are recommended guidelines for OSHA Compliance Safety and Health Officers (CSHOs), please see the corresponding OSHA method reference for complete details.

Wipe Method
Sampler/Sampling media
 
 

 

Bulk Method
Bulk Method
 
 

 

On-Site Screening Techniques
Device Detector tubes Detector tubes Detector tube Detector tube Detector tube CMS Chip
Model/Type Dräger - Ethylene oxide 1/a, 6728961; Ethylene oxide 25/a, 6728241 Gastec 163LL, 163L Gastec 163 Matheson-Kitagawa 8014-122SC Matheson-Kitagawa 8014-122SA Ethylene oxide, 0.4-5 ppm range
Sampling information
(see manufacturer instructions)
1/a: 20 strokes, 1-15 ppm range, uncertainty 32%. 25/a: 30 strokes, 10-500 ppm range, uncertainty 32% 163 LL: 2-4 strokes, 0.5-10 ppm range, uncertainty 25% for 0.1-0.5 ppm, 16% for 1-5 ppm. 163L: 1-4 strokes, 0.1-350 ppm range, uncertainty 25% for 1-20 ppm, 16% for 20-100 ppm 1 stroke, 0.02-3% range, uncertainty 16% for 0.05-1%, 8% for 1-3% follow mfr instructions, approx 1-15 ppm range follow mfr instructions, approx 0.01-4% range
Exposure Limits
OSHA PEL
8-hour TWA
(ST) STEL
(C) Ceiling
Peak
NIOSH REL
Up to 10-hour TWA
(ST) STEL
(C) Ceiling
ACGIH TLV©
8-hour TWA
(ST) STEL
(C) Ceiling
CAL/OSHA PEL
8-hour TWA
(ST) STEL
(C) Ceiling
Peak
PEL-TWA
 
 

1 ppm [0.5 ppm Action Level]

REL-TWA
 
 

<0.1 ppm (<0.18 mg/m³)

TLV-TWA
 
 

1 ppm [1990]

PEL-TWA
 
 

1 ppm (2 mg/m³)

PEL-STEL
 
 

 

REL-STEL
 
 

 

TLV-STEL
 
 

 

PEL-STEL
 
 

5 ppm

PEL-C
 
 

5 ppm [15 minute excursion limit]

REL-C
 
 

5 ppm (9 mg/m³)[10 minutes]

TLV-C
 
 

 

PEL-C
 
 

 

Skin notation
 
 

N

Skin notation
 
 

N

Skin notation
 
 

N

Skin notation
 
 

N

Notes:
 
 

See 29 CFR 1910.1047 Ethylene oxide

Notes:
 
 

CARCINOGEN (Ca): REDUCE EXPOSURE TO LOWEST FEASIBLE CONCENTRATION. See Appendix A

Notes:
 
 

 

Notes:
 
 

See also 5220. Ethylene Oxide

Health factors:  See NIH-NLM PubChem. IDLH
 
 

800 ppm

Carcinogenic classifications: IARC-1, NIOSH-Ca, NTP-K, OSHA-Ca, TLV-A2 Notes:
 
 

Ca

AIHA emergency response planning guidelines - ERPG-1/ERPG-2/ERPG-3:
 
 

--/50 ppm/500 ppm

Last Updated Date : 12/28/2020