ISOBUTANE

Chemical Identification
CAS #	75-28-5
Formula	C₄H₁₀
Synonyms	2-methylpropane

Physical Properties
Physical description	Colorless gas with a gasoline-like or natural gas odor.
Boiling point	10.8°F	Molecular weight	58.12
Freezing point/melting point	-216.9°F	Vapor pressure	3.1 atm at 70°F
Flash point	-117°F	Vapor density	2.06
Specific gravity	0.557	Ionization potential	10.74 eV
Lower explosive limit (LEL)	1.6%	Upper explosive limit (UEL)	8.4%
NFPA health rating	0	NFPA fire rating	4
NFPA reactivity rating	0	NFPA special instruction
Vapor hazard ratio (VHR)
Historical exceedance percentage
Target organs

Monitoring Methods Used by OSHA
Analyte code (IMIS no.)
Sampling group
Sampler/Sampling media
Sampling time^*
Sampling volume (TWA)^*
Sampling flow rate (TWA)^*
Sampling volume (STEL/Peak/C)^*
Sampling flow rate (STEL/Peak/C)^*
Analytical method instruments
Method reference
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.

Bulk/Wipe Method
Wipe Sampler/Sampling media
Bulk Method

On-Site Screening Techniques
Device	Detector tube	Detector tube	Detector tube
Model/Type	Gastec 103	Gastec 104	Matheson-Kitagawa 8014-113SB
Sampling information (see manufacturer instructions)	0.5-3 strokes, approx 0.02-1.7% range, uncertainty 16%	1 stroke, approx 10-3080 ppm range, uncertainty 16%	1 stroke, approx 25-1200 ppm 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		REL-TWA	800 ppm (1900 mg/m³)	TLV-TWA		PEL-TWA
PEL-STEL		REL-STEL		TLV-STEL	1000 ppm [2012]	PEL-STEL
PEL-C		REL-C		TLV-C		PEL-C
Skin notation	NA	Skin notation	N	Skin notation	N	Skin notation	NA
Notes: Not established		Notes:		Notes: (EX) Explosion hazard: the substance is a flammable asphyxiant or excursions above the TLV could approach 10% of the LEL		Notes: Not established
Health factors: See NIH-NLM PubChem.		IDLH
Carcinogenic classifications: Not listed		Notes:
AIHA emergency response planning guidelines - ERPG-1/ERPG-2/ERPG-3:

Additional Resources and Literature References

NOAA: CAMEO Chemicals - Isobutane

NIOSH: Pocket Guide to Chemical Hazards - Isobutane

Literature References

ACGIH: Documentation of the Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs) - Butane, isomers. See annual publication for most recent information.
Fuke, C., et al.: A fatal case considered to be due to cardiac arrhythmia associated with butane inhalation. Leg. Med. (Tokyo) 4(2): 134-138, 2002.
Galvin, J.B. and Bond, G.: Isobutane CAS# 75-28-5. J. Toxicol. Environ. Health, Part A 58(1-2): 3-22, 1999.
Pohanish, R.P. (editor): Butanes. In, Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 1. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 386-388.
Rohrig, T.P.: Sudden death due to butane inhalation. Am. J. Forensic Med. Pathol. 18(3): 299-302, 1997.
Tsukamoto, S., Chiba, S., Muto, T., Ishikawa, T. and Shimamura, M.: Study on the metabolism of volatile hydrocarbons in mice-propane, n-butane, and iso-butane. J. Toxicol. Sci. 10(4): 323-332, 1985.

Last Updated Date : 12/31/2020

ISOBUTANE

Chemical Identification

Physical Properties

Monitoring Methods Used by OSHA

Bulk/Wipe Method

On-Site Screening Techniques

Exposure Limits

Additional Resources and Literature References