Synonyms: Isopentane; Ethyldimethylethane; Isoamylhydride
OSHA IMIS Code Number: R228
Chemical Abstracts Service (CAS) Registry Number: 78-78-4
Other Chemical Abstracts Service (CAS) Registry Numbers: 109-66-0 (Pentane)
NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: EK4430000
Chemical Description and Physical Properties:
colorless liquid, with characteristic odor
molecular weight: 72.17
vapor pressure: 79 kPa at 20°C
molecular formula: C5H12
boiling point: 28°C
melting point: -160°C
There is no specific OSHA PEL or NIOSH REL for this compound.
OSHA Permissible Exposure Limit (PEL) (for Pentane):
General Industry: 29 CFR 1910.1000 Table Z-1 - 1000 ppm, 2950 mg/m3 TWA
Construction Industry: 29 CFR 1926.55 Appendix A - 500 ppm, 1500 mg/m3 TWA
Maritime: 29 CFR 1915.1000 Table Z-Shipyards - 500 ppm, 1500 mg/m3 TWA
National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL) (for Pentane): 120 ppm; 350 mg/m3 TWA; 610 ppm, 1800 mg/m3 Ceiling (15 Minutes)
American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): 600 ppm, 1770 mg/m3 TWA (TLV listed under Pentane, All isomers)
Potential Symptoms: Eye, nose, throat and skin irritation; cough, sore throat; headache, shortness of breath; dizziness, drowsiness, loss of coordination, unconsciousness; irregular heartbeat; redness, dryness and cracking of skin; rash or burning sensation on contact with liquid; INGES ACUTE: Abdominal pain, nausea, vomiting; chemical pneumonitis (following aspiration of liquid)
Health Effects: Irritation-Eyes, Nose, Throat, Skin---Mild (HE16); Narcosis (HE8); Explosive, Flammable (HE18)
Affected Organs: Eyes, skin, respiratory system, CNS
- OSHA does not have a PEL for 2-methyl butane.
- Vapor/air mixtures are explosive.
- No toxic effects of the vapor have been reported at levels less than 14,000 ppm, the minimum explosive limit in air.
- Metabolized in mice or by animal liver microsomes to various methyl-butanol derivatives and to 3-methyl-2-butanone. Potential use of any of these metabolites as markers of occupational exposure has not been reported.
- International Chemical Safety Cards (WHO/IPCS/ILO): Isopentane.
- Chiba, S. and Oshida, S.: Metabolism and toxicity of n-pentane and isopentane [Japanese]. Nippon Hoigaku Zasshi 45(2): 128-137, 1991.
- Galvin, J.B. and Marashi, F.: 2-Methylbutane (isopentane). CAS# 78-78-4. J. Toxicol. Environ. Health A 58(1-2): 23-33, 1999.
- Pohanish, R.P. (editor): Isopentane. In, Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 2. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 1341-1342.
Date Last Revised: 01/26/2005
Primary Laboratory Sampling/Analytical Method (SLC1):
- sampling media: Charcoal Tube (100/50 mg sections, 20/40 mesh)
analytical solvent: (99:1) Carbon Disulfide:Dimethylformamide
maximum volume: 4 Liters
maximum flow rate: 0.2 L/min
current analytical method: Gas Chromatography; GC/FID
method reference: NIOSH Analytical Method (NIOSH 1500 [127 KB PDF, 8 pages])
method classification: Partially Validated
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