# NIOSH Pocket Guide to Chemical Hazards
Isobutane | CAS 75-28-5
CH3CH(CH3)2 | RTECS TZ4300000
Synonyms & Trade Names 2-Methylpropane [Note: Also see specific listing for n-Butane.] | DOT ID & Guide 1075 115 1969 115
Exposure Limits | NIOSH REL: TWA 800 ppm (1900 mg/m3)
OSHA PEL†: none
IDLH N.D. | Conversion 1 ppm = 2.38 mg/m3
Physical Description Colorless gas with a gasoline-like or natural gas odor. [Note: Shipped as a liquefied compressed gas. A liquid below 11°F.]
MW: 58.1 | BP: 11°F | FRZ: -255°F | Sol: Slight
VP(70°F): 3.1 atm | IP: 10.74 eV | RGasD: 2.06 |
Fl.P: NA (Gas) | UEL: 8.4% | LEL: 1.6% |
Flammable Gas Class IA Flammable Liquid
Incompatibilities & Reactivities Strong oxidizers (e.g., nitrates & perchlorates), chlorine, fluorine, (nickel carbonyl + oxygen)
Measurement Methods None available
Personal Protection & Sanitation Skin: Frostbite Eyes: Frostbite Wash skin: No recommendation Remove: When wet (flammable) Change: No recommendation Provide: Frostbite | First Aid (See procedures) Eye: Frostbite Skin: Frostbite Breathing: Respiratory support
Respirator Recommendations To be added later
Exposure Routes inhalation, skin and/or eye contact (liquid)
Symptoms Drowsiness, narcosis, asphyxia; liquid: frostbite
Target Organs central nervous system
See also: INTRODUCTION