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The following information relevant to Poisons Centres has been extracted from the CHEMINFO database produced by CCOHS. Complete CHEMINFO records also contain comprehensive hazard control and regulatory information. For more information about the complete CHEMINFO database contact CCOHS.
 
SECTION 1. CHEMICAL IDENTIFICATION

CHEMINFO Record Number: 73
CCOHS Chemical Name: Isobutane
CAS Registry Number: 75-28-5
UN/NA Number(s): 1969 1075
RTECS Number(s): TZ4300000
EU EINECS/ELINCS Number: 200-857-2
Chemical Family: Saturated aliphatic hydrocarbon / paraffin / alkane / butane isomer
Molecular Formula: C4-H10
Structural Formula: (CH3)2-CH-CH3

SECTION 2. DESCRIPTION

Appearance and Odour:
Colourless, odourless gas at low concentrations. Has a characteristic natural gas or gasoline-like odour when present in high concentrations.(2,26) Commercial grade may have an added odourant (consult supplier MSDS).

Odour Threshold:
Odourless, odorant may be added by supplier.(27)

Warning Properties:
POOR - odourless or has faint odour at high concentrations; odorant may be added by supplier.

Composition/Purity:
Technical and higher grades of isobutane are at least 98.5% pure and are not odourized. Some of the impurities present in these grades are nitrogen, oxygen, sulfur, water, ethane, ethylene, propane, propylene, n-butane, unsaturated butanes, and other higher alkane compounds.(28,29) High purity grades, greater than 99.9%, may contain traces (less than 300 ppm) of 1,3-butadiene while lower grades may contain approximately 0.1% of 1,3-butadiene. Consult with your supplier regarding product purity. 1,3-Butadiene is a probable human carcinogen (IARC Group 2A) and mutagenic. If 1,3-butadiene is present in isobutane at concentrations of 0.1% or greater, then the mixture is considered carcinogenic and mutagenic. This review is for isobutane containing less than 0.1% 1,3-butadiene. Refer to the CHEMINFO review for comprehensive information on the hazards and control measures for 1,3-butadiene.

Uses and Occurrences:
Commercial isobutane is used as a fuel (source of energy) and to calibrate instruments. Also used as a refrigerant, an aerosol propellant, in the production of high-octane gasoline blends, and in manufacture of unsaturated alkenes and other organic chemicals and polymers. The main sources of isobutane are oil and natural gas fields. Isobutane is also generated as a by-product when crude oil is refined.(2,31)


SECTION 3. HAZARDS IDENTIFICATION

EMERGENCY OVERVIEW:
Colourless, odourless gas at low concentrations. Characteristic natural gas or gasoline-like odour at high concentration. Commercial grade may have added odourant. EXTREMELY FLAMMABLE GAS. COMPRESSED GAS or LIQUEFIED GAS. Gas is heavier than air and may spread long distances and will accumulate at low points (e.g. open or closed drain). Distant ignition and flashback are possible. Essentially non-toxic at low concentrations. Asphyxiant. At high concentrations, isobutane gas may reduce oxygen available for breathing. Can accumulate in confined spaces, resulting in a fire and toxicity hazard. Mild central nervous system depressant. High vapour concentrations may cause headache, nausea, dizziness, drowsiness, incoordination, and unconsciousness. Rapid evaporation of liquefied gas from cylinder can cause cold burns or frostbite. NOTE: Some grades of isobutane may contain 1,3-butadiene, which is carcinogenic and mutagenic. If 1,3-butadiene is present in isobutane at a concentration of more than 0.1%, the mixture is considered carcinogenic and mutagenic. For more information, refer to the CHEMINFO review of 1,3-butadiene.



POTENTIAL HEALTH EFFECTS

Effects of Short-Term (Acute) Exposure

Inhalation:
At low concentrations, isobutane is essentially non-toxic. At high concentrations, isobutane can cause depression of the central nervous system (CNS) with symptoms such as headache, nausea, dizziness, drowsiness and confusion, based on animal information. It is expected to cause unconsciousness (narcosis) due to CNS depression at approximately 24000 ppm (2.4%).(20) (Note that isobutane is extremely flammable (lower explosive limit: 1.8%)). No health effects were observed in 8 volunteers who inhaled 250, 500 or 1000 ppm isobutane for 1 minute to 8 hours. Exposure to 500 ppm for 1, 2 or 8 hours for 2 weeks (5 d/wk) also produced no harmful effects.(12)
Isobutane gas concentrations can become so high that oxygen is displaced, especially in confined spaces. Life-threatening asphyxiation (suffocation) may result. The available oxygen should be a minimum of 18% or harmful effects will result.(21,22) Isobutane displaces oxygen to 18% in air when present at 14% (140000 ppm). Effects of oxygen deficiency are: 12-16% - breathing and pulse rate are increased, with slight muscular incoordination; 10-14% - emotional upsets, abnormal fatigue from exertion, disturbed respiration; 6-10% - nausea and vomiting, inability to move freely, collapse, possible lack of consciousness; below 6% - convulsive movements, gasping, possible respiratory collapse and death. Since exercise increases the body's need for oxygen, symptoms will occur more quickly during exertion in an oxygen-deficient environment.(21,22) Survivors of oxygen deprivation may show damage to some or all organs including the central nervous system and the brain. These effects may or may not be reversible with time, depending on the degree and duration of the low oxygen and the amount of tissue injury.(22)
Isobutane and some other closely related aliphatic hydrocarbons (propane and butane) are weak cardiac sensitizers in humans following inhalation exposures to high concentrations. Cardiac sensitizers may cause the sudden onset of an irregular heartbeat (arrhythmia) and, in some cases, sudden death. Sudden deaths have been reported in cases of substance abuse involving isobutane, butane and propane. Under stressful conditions and with exposure to high concentrations, the effects of cardiac sensitization may be important for some these hydrocarbon gases. The asphyxiant effects of isobutane may enhance cardiac sensitization.(3)

Skin Contact:
Isobutane gas is not a skin irritant.
Contact with liquefied gas can cause cold burns or frostbite. Symptoms of mild frostbite include numbness, prickling and itching in the affected area. Symptoms of more severe frostbite include a burning sensation and stiffness of the affected area. The skin may become waxy white or yellow. Blistering, tissue death and gangrene may also develop in severe cases.

Eye Contact:
Isobutane gas is not irritating to the eyes.
Contact with liquefied gas can cause freezing of the eye. Permanent eye damage or blindness could result.

Ingestion:
Not applicable to gases.

Effects of Long-Term (Chronic) Exposure

Isobutane is not expected to cause health effects following long-term exposure. No conclusions can be drawn from a single case report describing harmful effects on the liver, since there was concurrent exposure to other potentially harmful chemicals. No significant long-term effects were reported in the animal studies located.

Liver:
No conclusions can be drawn from a single case report, since it possible to directly attribute the observed effects to isobutane exposure.
A 63-year-old man developed signs of liver injury (abnormal liver function test results). He had been exposed to an adhesive 3 hours/time, 2-3 times/week for approximately 2 years in a poorly ventilated garage. During this time, he experienced symptoms of drowsiness and nausea. The adhesive contained a propane/butane/isobutane propellant (30-35%), petroleum distillates (25-35%), pentane (10-15%) and acetone (1-5%). He stopped using the adhesive and liver tests returned to normal within 4 weeks.(23)

Carcinogenicity:
No human or animal information for isobutane was located.

Some grades of isobutane may contain 1,3-butadiene, which is classified by the International Agency for Research on Cancer (IARC) as a probable human carcinogen (Group 2A). If 1,3-butadiene is present in isobutane at a concentration of more than 0.1%, the mixture is considered carcinogenic. For more information, refer to the CHEMINFO review of 1,3-butadiene.

The International Agency for Research on Cancer (IARC) has not evaluated the carcinogenicity of this chemical.

The American Conference of Governmental Industrial Hygienists (ACGIH) has not assigned a carcinogenicity designation to this chemical.

The US National Toxicology Program (NTP) has not listed this chemical in its report on carcinogens.

Teratogenicity and Embryotoxicity:
No animal or human information was located. Isobutane is not expected to cause developmental effects.

Reproductive Toxicity:
No animal or human information was located. Isobutane is not expected to cause reproductive effects.

Mutagenicity:
No animal or human information was located. Negative results were obtained in short-term tests.

Some grades of isobutane may contain 1,3-butadiene, which is mutagenic. If 1,3-butadiene is present in isobutane at a concentration of more than 0.1%, the mixture is considered mutagenic. For more information, refer to the CHEMINFO review of 1,3-butadiene.

Toxicologically Synergistic Materials:
No information was located.

Potential for Accumulation:
Does not accumulate.


SECTION 4. FIRST AID MEASURES

Inhalation:
This is chemical is extremely flammable. Take proper precautions (e.g. remove any sources of ignition). In general, this gas has very low toxicity, but it can act as a central nervous system depressant and an asphyxiant at high concentrations. If the victim has been knocked down, wear appropriate protective equipment, and use the buddy system. Remove source of contamination or move victim to fresh air. If breathing is difficult, trained personnel should administer oxygen. If breathing has stopped, trained personnel should begin artificial respiration (AR) or, if the heart has stopped, cardiopulmonary resuscitation (CPR) or automated external defibrillation (AED) immediately. Quickly transport victim to an emergency care facility.

Skin Contact:
LIQUEFIED GAS: Quickly remove victim from source of contamination and briefly flush with lukewarm, gently flowing water until the chemical is removed. DO NOT attempt to rewarm the affected area on site. DO NOT rub area or apply dry heat. Gently remove clothing or jewelry that may restrict circulation. Carefully cut around clothing that sticks to the skin and area with a sterile dressing. DO NOT allow victim to drink alcohol or smoke. Quickly transport victim to an emergency care facility. GAS: Not applicable. No effects expected.

Eye Contact:
LIQUEFIED GAS: Quickly remove victim from source of contamination. Immediately and briefly flush with lukewarm, gently flowing water until the chemical is removed. DO NOT attempt to rewarm. Cover both eyes with a sterile dressing. DO NOT allow victim to drink alcohol or smoke. Quickly transport victim to an emergency care facility. GAS: Not applicable. No effects expected.

Ingestion:
Ingestion is not an applicable route of exposure for gases.

First Aid Comments:
Provide general supportive measures (comfort, warmth, rest).
Consult a doctor and/or the nearest Poison Control Centre for all exposures except minor instances of inhalation or skin contact.
Some first aid procedures recommended above require advanced first aid training. Protocols for undertaking advanced procedures must be developed in consultation with a doctor and must be routinely reviewed.
All first aid procedures should be periodically reviewed by a doctor familiar with the material and its condition of use in the workplace.



SECTION 5. FIRE FIGHTING MEASURES

Flash Point:
Flammable gas

Lower Flammable (Explosive) Limit (LFL/LEL):
1.8% (8)

Upper Flammable (Explosive) Limit (UFL/UEL):
8.4% (8)

Autoignition (Ignition) Temperature:
462 deg C (864 deg F) (2)

Sensitivity to Mechanical Impact:
Not sensitive.

Sensitivity to Static Charge:
Liquefied isobutane can accumulate electrostatic charge by flow, friction in pipes, splashing or agitation. Isobutane gas in the flammable range can be easily ignited by an electrostatic discharge of sufficient energy (e.g. brush discharge).

Electrical Conductivity:
Not applicable for gas. Not available for liquefied gas. Based on isobutane's chemical properties and dielectric constant, the electric conductivity for liquefied isobutane is expected to be less then 50 pS/m.

Minimum Ignition Energy:
Approximately 0.21 mJ based on comparison to n-butane and isopentane.(8)

Combustion and Thermal Decomposition Products:
Carbon monoxide, carbon dioxide, water and toxic and irritating fumes.

Fire Hazard Summary:
EXTREMELY FLAMMABLE COMPRESSED OR LIQUEFIED GAS. Can readily form explosive mixtures with air, which are easily ignited by a static charge. Liquefied isobutane accumulates static charge. Liquefied isobutane vapourizes under normal conditions and produces 230 volumes vapour for every one volume of liquid. Ignition of a large volume of isobutane vapour intermixed with air causes sudden expansion and turbulence resulting in an explosion known as vapour cloud explosion. Large spills of liquefied isobutane form rapidly dense flammable vapours, which will travel over long distances and will create a flash back hazard. The gas can accumulate in confined spaces and low areas, resulting in an explosion or toxicity hazard. During a fire, toxic gases may be generated. Heat from a fire can cause a rapid build-up of pressure inside cylinders or tanks, which may cause explosive rupture and a sudden release of large amounts of extremely flammable gas.

Extinguishing Media:
Dry chemical powder and high-expansion foam. Foam manufacturers should be consulted for recommendations regarding types of foams and application rates.(35,36)

Extinguishing Media to be Avoided:
Carbon dioxide, low expansion foams, and direct application of water on liquefied isobutane gas. Under certain conditions, discharge of carbon dioxide produces electrostatic charges that could create a spark and ignite isobutane.(36,37)

Fire Fighting Instructions:
Evacuate area. Fight fire from a protected location or maximum distance possible. Approach fire from upwind to avoid toxic decomposition products. For fires involving flammable gases, the best procedure is to stop the flow of gas before attempting to extinguish the fire. It is extremely dangerous to extinguish the fire, while allowing continued flow of the gas. The gas could form an explosive mixture with air and re-ignite resulting in a sudden violent flash fire, which may cause far more damage than if the original fire had been allowed to burn. In some cases, extinguishing the fire with dry chemical powder may be necessary to permit immediate access to valves to shut off the flow of gas. However, this must be done carefully. If it is not possible to stop the flow of gas and if there is no risk to the surrounding area, allow the fire to continue burning while protecting exposed materials with water spray, to prevent ignition of other combustible materials. DO NOT direct water at the source of leak or at safety devices; icing may occur which can result in blockage of pressure release valves. Liquefied isobutane fires may be controlled with high-expansion foam blankets. The resulting solutions may be flammable. Dike foam solutions for appropriate disposal. Heat from a fire can cause a rapid build-up of pressure inside cylinders or tanks, which may cause explosive rupture. If tanks are directly exposed to flames an explosive rupture may occur below the relief valve set, sending tank fragments in any direction and far away (e.g. 2200 meters). Withdraw immediately in case of rising sound from venting safety device or any discolouration of tank due to fire. Cool fire-exposed cylinders, tanks, equipment or pipelines by applying hose streams, to minimize the risk of rupture. Cooling should begin as soon as possible (within several minutes) and should concentrate on any unwetted portions of the container. Apply water from the side and a safe distance. DO NOT direct water at open or leaking cylinders and take precautions not to get water inside a container or cylinder. Reverse flow into cylinder may cause rupture. No part of a cylinder should be subjected to a temperature higher than 52 deg C (approximately 125 deg F). Cooling should continue until well after the fire is out. Isolate cylinders and other containers exposed to heat but not yet directly involved in the fire and protect personnel. Move cylinders from fire area only if this can be done without risk. Stay away from ends of tanks, but be aware that flying material (shrapnel) from ruptured tanks or cylinders may travel in any direction. For an advanced or a massive fire in a large area, use unmanned hose holder or monitor nozzles; if this is not possible withdraw from fire area and allow fire to burn. After the fire has been extinguished, the resulting foam solutions of isobutane may be flammable. Explosive atmospheres may be present. Before entering such an area, especially confined areas, check the atmosphere with an appropriate monitoring device. Cylinders or tanks that have been involved in a fire should not be approached until they have been completely cooled down.

Protection of Fire Fighters:
Isobutane is only slightly hazardous to health. However, it can displace oxygen, reducing the amount available for breathing. Firefighters may enter the area if positive pressure self-contained breathing apparatus (NIOSH approved or equivalent) and full Bunker Gear is worn.



NATIONAL FIRE PROTECTION ASSOCIATION (NFPA) HAZARD IDENTIFICATION

NFPA - Health: 0 - Exposure, under fire conditions, would be no more hazardous than an ordinary combustible material.
NFPA - Flammability: 4 - Will rapidly or completely vaporize at atmospheric pressure and normal ambient temperature, or readily disperse in air and burn readily.
NFPA - Instability: 0 - Normally stable, even under fire conditions, and not reactive with water.

SECTION 9. PHYSICAL AND CHEMICAL PROPERTIES

Molecular Weight: 58.1

Conversion Factor:
1 ppm = 2.37 mg/m3; 1 mg/m3 = 0.421 ppm at 25 deg C (calculated)

Melting Point: -138.3 deg C (-216.9 deg F) (32)
Boiling Point: -11.7 deg C (11 deg F) (32)
Relative Density (Specific Gravity): 0.552 at 25 deg C (water = 1) (2)
Solubility in Water: Practically insoluble (49 mg/L) at 25 deg C (32)
Solubility in Other Liquids: Moderately soluble in relatively non-polar solvents like toluene, chloroform, and diethyl ether and ethanol. Not soluble in polar solvents like methanol.(33)
Coefficient of Oil/Water Distribution (Partition Coefficient): Log P(oct) = 2.76 (32)
pH Value: Not applicable
Vapour Density: 2.00 (air = 1) (calculated)
Vapour Pressure: 311 kPa (2332 mm Hg) at 21.1 deg C (2)
Vapour Pressure at 50 deg C: 690 kPa (5175 mm Hg) (estimated)
Saturation Vapour Concentration: Not applicable (gas)
Evaporation Rate: Not applicable for gas. Liquefied isobutane will evaporate rapidly at room temperature.
Critical Temperature: 135 deg C (275 deg F) (2)
Critical Pressure: 3638 kPa (36.0 atm) (2)

Other Physical Properties:
DIELECTRIC CONSTANT: Less than 1.8 at 27 deg C and 34700 kPa. (dimensionless) (34)


SECTION 10. STABILITY AND REACTIVITY

Stability:
Stable

Hazardous Polymerization:
Does not occur

Incompatibility - Materials to Avoid:
The risk of a hazardous incident occurring due to accidental mixing of isobutane with other substances is low because isobutane only reacts with a very small number of chemical classes that are commonly used in the workplace. If an accidental mixing does occur, these few reactions may be severe.

STRONG OXIDIZING AGENTS (e.g. peroxides, perchlorates) - Increases the risk of fire and explosion. Reaction may be delayed.(39)
HALOGEN COMPOUNDS (e.g. chlorine, and bromine) - Risk of fire and explosion. Fluorine gas reacts explosively.(40) Mixtures with around 20% or more of chlorine are explosive. However, if any mixture of isobutane and chlorine gas is exposed to direct sunlight there is almost always an explosion.(41) The presence of some metallic salts or oxides (e.g. ferric chloride, copper oxide) or metals (e.g. mercury, zinc) increases the reactivity with the halogen compounds.(39,41,42) Reaction with iodine is not vigorous.

Hazardous Decomposition Products:
Isobutane reacts very slowly with air to form tert-butylhydroperoxide and di-tert- butylperoxide. These compounds are unstable oxidizers and may decompose violently when heated. Corrosive acidic compounds may also form. The rate of peroxide formation increases on exposure to heat, light or on prolonged exposure to air.(38)

Conditions to Avoid:
Static charge, sparks, open flames and other ignition sources

Corrosivity to Metals:
Pure isobutane gas or liquefied gas is not corrosive to aluminum or carbon steel.(43)

Corrosivity to Non-Metals:
Isobutane gas is not corrosive to fluorinated plastics, polyvinyl chloride (PVC), polyurethane, and high-density polyethylene (HDPE).(30)


SECTION 11. TOXICOLOGICAL INFORMATION

LC50 (male mouse): 368000 ppm (36.8%) (4-hour exposure); cited as 520400 ppm (52.4%) (2-hour exposure) (oxygen concentration maintained) (4)
LC50 (rat): greater than 13023 ppm (1.3%) (4-hour exposure) (18, unconfirmed)
LC50 (rat): 570000 ppm (cited as 57%) (15-minute exposure)* (17)
*LC50 values obtained with 15-minute exposure durations cannot be reliably converted to 4-hour exposure durations.

Eye Irritation:

No specific information was located.

Application of a hair spray containing 22% isobutane resulted in mild, temporary irritation in rabbits.(7)

Skin Irritation:

No specific information was located.

Application of a formulation containing 83.2% isobutane resulted in moderate irritation in rabbits. However, application of other formulations containing 74.25-89.55% isobutane only produced mild irritation in rabbits.(7) The presence of other chemicals in the formulations probably influenced the results.

Effects of Short-Term (Acute) Exposure:

At high concentrations, isobutane can produce central nervous system depression. It is a weak cardiac sensitizer.

Inhalation:
Head-only inhalation of isobutane did not produce upper airway irritation in male mice breathing 1.25% (12460 ppm) for 1 minute, with recovery for 10 minutes, another exposure for 1 minute and a 5-minute recovery.(18, unconfirmed) Mice exposed to 15% (150000 ppm), 20% (200000 ppm) or 23% (230000 ppm) showed signs of light anesthesia (unable to maintain an upright position) within 60, 17 and 26 minutes, respectively. Deaths occurred in 6/10 mice exposed to 41% (410000 ppm) and 10/10 mice exposed to 52% (520000 ppm) for two hours.(16) Exposure to 20% (200000 ppm) for 10 minutes produced central nervous system (CNS) effects (incoordination and loss of righting reflex) in 50% of the exposed rats (6/group).(17) No signs of toxicity or harmful kidney effects were observed in male rats exposed to 44-4437 ppm of a mixture of C4 and C5 hydrocarbons (including 25% by weight isobutane) for 21 days (6 hr/d; 5 d/wk).(14) Isobutane is a weak cardiac sensitizer in dogs and rats (high concentrations can cause abnormal heartbeat in animals under stress). Anesthetized monkeys inhaled 5-10% (50000-100000 ppm) isobutane for 5 minutes through a tracheal cannula. No significant cardiac effects were observed. A 10% concentration caused slight, but not statistically significant, increase in pulmonary resistance and in depressed respiratory minute volume.(6) When monkeys (3/group) inhaled 5 or 10% (50000 or 100000 ppm) isobutane for 5-minute periods alternating with 10-minute exposures to room air, cardiac abnormalities (arrhythmia and myocardial depression) were detected.(25) Cardiac sensitization to adrenaline was observed in 50% of dogs (number not specified) exposed to 7% (70000 ppm) for 5 minutes.(17) Intravenous injection with epinephrine following 10 minutes of inhalation exposure to 15-90% (150000-900000 ppm) isobutane mixed with oxygen caused cardiac sensitization in 2/2 anesthetized dogs.(19) These studies are limited by the small number of animals used and/or incomplete reporting. Dogs were injected with epinephrine, exposed to isobutane for 5 minutes and then injected with epinephrine again. Exposure to 2.5% (25000 ppm) isobutane caused no marked responses in the hearts of 12 dogs. At 5.0% (50000 ppm), isobutane caused a marked response (4/12 dogs) and at 10-20% (100000-200000 ppm), marked cardiac responses were observed in all dogs (6/6).(1) Anesthetized mice inhaling 20 or 40% (200000 or 400000 ppm) isobutane developed cardiac sensitization to injected epinephrine. No cardiac sensitization was observed following inhalation of 10% (100000 ppm) isobutane and epinephrine injection. Inhalation of 10, 20 or 40% isobutane alone did not induce cardiac sensitization.(24)

Effects of Long-Term (Chronic) Exposure:

Inhalation:
Rats (20 males and 10 females/group) were exposed to 1000 or 4500 ppm isobutane:isopentane (50:50 wt.%) for 13 weeks (6 hr/d; 5 d/wk). Possible treatment-related, but not dose-related, effects included transient hunched posture and/or reduced activity and intermittent tremor. In males exposed to 1000 ppm, statistically significant mild kidney injury was observed in animals evaluated following an interim sacrifice at day 28. This effect was not observed in animals autopsied at study termination (13 weeks).(15) The kidney effects (hyaline droplet accumulation) observed in this study are commonly seen in untreated male rats and are considered reversible. Rabbits and monkeys were exposed for 90 days to 3 different aerosol products (2 hair sprays and a deodorant) containing isobutane. No significant toxic effects were seen in any of the studies.(7)

Mutagenicity:
Negative results were obtained in a short-term test using bacteria.
In a modified Ames test, isobutane (97.4 and 96.3% pure) was not mutagenic to 5 strains of bacteria, with and without metabolic activation. Concentrations of 5-50% were tested. Weak cytotoxicity was seen at 50%.(13)


SECTION 16. OTHER INFORMATION

Selected Bibliography:
(1) Reinhardt, C.F., et al. Cardiac arrhythmias and aerosol sniffing. Archives of Environmental Health. Vol. 22 (1971). p. 265-279
(2) Yaws, C.L. Matheson gas data book. 7th ed. McGraw-Hill, 2001. p. 486-489
(3) Aliphatic hydrocarbon gases: alkanes (C1-C4). In: Documentation of threshold limit values and biological exposure indices. 7th ed. (Suppl.). American Conference of Governmental Industrial Hygienists, 2004
(4) Aviado, D.M., et al. Isobutane. In : Non-fluorinated propellants and solvents for aerosols: hydrocarbon repellants. CRC Press, Inc., 1977. p. 61-72
(5) Low, K.L., et al. Isobutane. In : Ethel Browning's toxicity and metabolism of industrial solvents. 2nd ed. Vol. 1 : hydrocarbons. Edited by R. Snyder. Elsevier, 1987. p. 273-278
(6) Aviado, D.M., et al. Toxicity of aerosol propellants in the respiratory and circulatory systems. VIII. Respiration and circulation in primates. Toxicology. Vol 3 (1975). p. 241-252
(7) Final report of the safety assessment of isobutane, isopentane, n-butane, and propane. Journal of the American College of Toxicology. Vol. 1, no. 4 (1982). p. 127-142
(8) Fire protection guide to hazardous materials. 13th ed. Edited by A.B. Spencer, et al. National Fire Protection Association, 2002. NFPA 325
(9) NIOSH pocket guide to chemical hazards. NIOSH, June 1994. p. 176-177
(10) Forsberg, K., et al. Quick selection guide to chemical protective clothing. 4th ed. Van Nostrand Reinhold, 2002
(11) European Communities (EC). Commission Directive 2001/59/EC. Aug. 6, 2001
(12) Stewart, R.D. et al. Acute and repetitive human exposure to isobutane. Scandinavian journal of work, environment and health. Vol. 3 (1977). p. 234-243
(13) Kirwin, C.J., et al. In vitro microbiological mutagenicity studies of hydrocarbon propellants. Journal of the Society of Cosmetics Chemistry. Vol. 31 (Dec. 1980). p. 367-370
(14) Halder, C.A., et al. Gasoline vapor exposures. Part II. Evaluation of the nephrotoxicity of the major C4/C5 hydrocarbon components. American Industrial Hygiene Association Journal. Vol. 47, no. 3 (Mar. 1986). p. 173- 175
(15) Aranyi, C., et al. Absence of hydrocarbon-induced nephropathy in rats exposed subchronically to volatile hydrocarbon mixtures pertinent to gasoline. Toxicology and Industrial Health. Vol. 2 (1986). p. 85-98
(16) Stoughton, R.W., et al. The relative anaesthetic activity of the butanes and pentanes. Journal of Pharmacology and Experimental Therapeutics. Vol. 58 (1936). p. 74-77
(17) Clark, D.G., et al. Acute inhalation toxicity of some halogenated and non-halogenated hydrocarbons. Human Toxicology. Vol. 1, no. 3 (1982). p. 239-247
(18) Galvin, J.B., et al. Isobutane. CAS# 75-28-5. Journal of Toxicology and Environmental Health, Part A. Vol. 58, no. 1-2 (1999). p. 3-22
(19) Krantz, Jr., J.C., et al. Anesthesia. XXXI. A study of cyclic and noncyclic hydrocarbons on cardiac automaticity. Journal of Pharmacology and Experimental Therapeutics. Vol. 94 (1948). p. 315-318
(20) Drummond, I. Light hydrocarbon gases: a narcotic, asphyxiant, or flammable hazard? Applied Occupational and Environmental Hygiene. Vol. 8 (1993). p. 120-125
(21) Leikauf, G.D., et al. Inorganic compounds of carbon, nitrogen and oxygen. In: Patty's Toxicology. 5th ed. Edited by E. Bingham, et al. Vol. 3. John Wiley & Sons, 2001
(22) Wilkenfeld, M. Simple asphyxiants. In: Environmental and Occupational Medicine. 3rd ed. Edited by W.N. Rom. Lippincott-Raven Publishers, 1998. p. 651-655
(23) Pyatt, J.R., et al. Abnormal liver function tests following inadvertent inhalation of volatile hydrocarbons. Postgraduate Medical Journal. Vol. 74, no. 878 (1998). p. 747-748
(24) Aviado, D.M., et al. Toxicity of aerosol propellants on the respiratory and circulatory systems. I. Cardiac arrhythmia in the mouse. Toxicology. Vol. 2 (1974). p. 31-42
(25) Belej, M.A., et al. Toxicity of aerosol propellants in the respiratory and circulatory systems. IV. Cardiotoxicity in the monkey. Toxicology. Vol. 2 (1974). p. 381-395
(26) Woker, G. The relations between structure and smell in organic compounds. Journal of Physical Chemistry. Vol. 10, no. 6 (1906). p. 455-473
(27) Compressed Gas Association. Handbook of compressed gases. 4th ed. Kluwer Academic Publishers, 1999. p. 27, 473-474
(28) Isobutane. Matheson Tri*Gas Website. Matheson Tri*Gas. Specification sheet. Available at: <www.matheson-trigas.com/mathportal/catalog/index.cfm>
(29) Isobutane. Sigma-Aldrich Website. Sigma-Aldrich Corporation. Specification sheet. Date unknown.
(30) Pruett, K.M. Chemical resistance guide for plastics: a guide to chemical resistance of engineering thermoplastics, fluoroplastics, fibers and thermoset resins. Compass Publications, 2000. p. 266-277
(31) Thompson, S.M., et al. Liquefied petroleum gases. In: Ullmann's encyclopedia of industrial chemistry. Available at: <www.mrw.interscience.wiley.com/ueic/ueic_search_fs.html> {Subscription required}
(32) Syracuse Research Corporation. The Physical Properties Database (PHYSPROP). Interactive PhysProp Database Demo. Date unknown. Available at: <www.syrres.com/esc/physdemo.html>
(33) Dean, J.A. Lange's handbook of chemistry. 2-Methylpropane. 15th ed. McGraw-Hill, Inc., 1999. p. 1.262
(34) Hayn, W.M. Measurement of densities and dielectric constants of liquid isobutane from 120 to 300 K at pressures to 35 MPa. Journal of Chemical Engineering Data. Vol. 28, no. 4 (1983). p.367-369.
(35) Lees, F. P. Loss prevention in the process industry: hazard identification, assessment control. 2nd ed. Vol. 2. Butterworth-Heinemann, 1996. p. 16/289
(36) Recommended practice for responding to hazardous materials incidents. National Fire Protection Association, 2002. NFPA 471
(37) Standard on carbon dioxide extinguishing systems. National Fire Protection Association, 2000. NFPA 12, Section 1-5.2.2
(38) Winkler, D.E. Liquid phase oxidation of isobutane. Industrial and Engineering Chemistry. Vol. 53, no. 8 (1961). p.655-658.
(39) Steacie, E.W.R. The kinetics of elementary reactions of the simple hydrocarbons. Chemical Reviews. Vol. 22, no. 2. (1938). p. 311-402
(40) Hauge, R.H. et al. Studies of the reaction of molecular fluorine with methane, acetylene, ethylene, allene, and other small hydrocarbons in matrices at low temperatures. Journal of the American Chemical Society. Vol. 101, no. 23 (1979). p. 6950
(41) Egloff, G. The halogenation of the paraffin hydrocarbons. Chemical Reviews. Vol. VIII, no. 1 (1930). p. 1-80
(42) Thomas, C.L. et al. Reactions of hydrocarbons in electrical discharges. Chemical Reviews. Vol. 28, no. 1 (1941). p. 1-70
(43) Pruett, K.M. Chemical resistance guide to metals and alloys: a guide to chemical resistance of metals and alloys. Compass Publications, 1995. p. 170-181
(44) Occupational Safety and Health Administration (OSHA). n-Butane. In: OSHA Analytical Methods Manual. Revision Date: Oct. 31, 2001. Available at: <www.osha-slc.gov/dts/sltc/methods/toc.html>

Information on chemicals reviewed in the CHEMINFO database is drawn from a number of publicly available sources. A list of general references used to compile CHEMINFO records is available in the database Help.


Review/Preparation Date: 2005-03-25

Revision Indicators:
Sampling/analysis 2005-03-31
Passive Sampling Devices 2005-03-31
Engineering controls 2005-04-04



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See Also:
        Butane (ICSC)
        Butane (PIM 945)
        n-Butane (CHEMINFO)