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CHEMINFO Record Number: 3
CCOHS Chemical Name: Isobutyl alcohol

Alcool isobutylique
Isopropyl carbinol

Chemical Name French: Alcool isobutylique
Chemical Name Spanish: Alcohol isobutílico
CAS Registry Number: 78-83-1
UN/NA Number(s): 1212
RTECS Number(s): NP9625000
EU EINECS/ELINCS Number: 201-148-0
Chemical Family: Saturated primary aliphatic alcohol / primary alkanol / primary alkyl alcohol / butanol / butyl alcohol
Molecular Formula: C4-H10-O
Structural Formula: (CH3)2-CH-CH2-OH


Appearance and Odour:
Clear, colourless liquid with a sweet, musty odour.(2,4b)

Odour Threshold:
0.66-40 ppm (detection) (2); 1.8-53 ppm (recognition) (2); 100 ppm (300 mg/m3) (irritation) (3)

Warning Properties:
NOT RELIABLE - odour threshold is about the same magnitude as TLV.

Available in pure forms.

Uses and Occurrences:
Primarily used as a solvent in paints and lacquers, in paint removers, cleaners and hydraulic fluids, and in the manufacture of isobutyl esters which are used in solvents, plasticizers, flavorings and perfumes.


Colourless liquid with a sweet musty odour. FLAMMABLE LIQUID AND VAPOUR. Vapour is heavier than air and may spread long distances. Distant ignition and flashback are possible. May be irritating to respiratory tract. Mild central nervous system depressant. High vapour concentrations may cause headache, nausea, dizziness, drowsiness and incoordination. Causes eye irritation. Aspiration hazard. Swallowing or vomiting of the liquid may result in aspiration into the lungs.


Effects of Short-Term (Acute) Exposure

Vapour may cause irritation to the nose and throat. Higher levels may cause severe irritation to the nose, throat and respiratory tract, cough and difficulty breathing and central nervous system depression effects such as nausea, vomiting, headache, dizziness and possibly unconsciousness.

Skin Contact:
Liquid may cause mild skin irritation. Isobutyl alcohol caused mild irritation in an animal test.(7)

Eye Contact:
High vapour levels can probably cause irritation. Contact with liquid can cause severe irritation based on animal information.(9)

Ingestion of isobutyl alcohol can cause central nervous system depression effects such as nausea, vomiting, stomach and chest pain, headache, weakness, dizziness and at higher doses collapse, coma and death. Liver and kidney damage may occur.
Aspiration (inhalation of fluid) of a small amount of undiluted alcohol may result in sudden respiratory failure and cardiac arrest, based on animal studies of various alcohols.(12)

Effects of Long-Term (Chronic) Exposure

NERVOUS SYSTEM: Seven laboratory workers were exposed to butyl alcohol and/or isobutyl alcohol, primarily by inhalation. Exposures were not quantified, but were thought to be excessive. Exposure durations ranged from 6 weeks to 2 years. Five workers experienced symptoms of central nervous system depression (nausea, dizziness, vomiting). One worker experienced marked ringing in the ears.(13)
SKIN: Repeated or prolonged contact may cause reddening, drying and cracking of the skin (dermatitis).


No human information is available. One limited animal study reported tumours.(11) This study does not meet current standards for carcinogenicity testing.

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 human or animal information is available.

Reproductive Toxicity:
No human information is available. No effects were seen in rats or rabbits, even at maternally toxic doses.

No human information is available. Isobutyl alcohol caused mutagenic effects in one bacterial test and not in another.

Toxicologically Synergistic Materials:
The toxicity of alcohols can be increased by exposure to chemicals such as chlorinated solvents and aromatic hydrocarbons.

Potential for Accumulation:
Does not accumulate. Absorbed isobutyl alcohol is largely broken down or changed in the body, then excreted through urine. A small amount is eliminated unchanged in the expired air and urine.


This product is flammable. Take proper precautions (e.g. remove any sources of ignition). Remove source of contamination or move victim to fresh air. Obtain medical advice.

Skin Contact:
No health effects expected. If irritation does occur, flush with lukewarm, gently flowing water for 5 minutes or until chemical is removed. If irritation persists, obtain medical advice.

Eye Contact:
Immediately flush the contaminated eye(s) with lukewarm, gently flowing water for 20 minutes or until the chemical is removed, while holding the eyelid(s) open. Take care not to rinse contaminated water into the unaffected eye or onto the face. Obtain medical attention immediately.

NEVER give anything by mouth if victim is rapidly losing consciousness, is unconscious or convulsing. Have victim rinse mouth thoroughly with water. DO NOT INDUCE VOMITING. Have victim drink 240 to 300 mL (8 to 10 oz.) of water to dilute material in stomach. If vomiting occurs naturally, have victim lean forward to reduce risk of aspiration. Repeat administration of water. If breathing has stopped, trained personnel should begin artificial respiration (AR) or, if the heart has stopped, cardiopulmonary resuscitation (CPR) immediately. Quickly transport victim to an emergency care facility.

First Aid Comments:
Provide general supportive measures (comfort, warmth, rest). Consult a doctor and/or the nearest Poison Control Centre for all exposures except under minor instances of inhalation or skin contact. All first aid procedures should be periodically reviewed by a doctor familiar with the material and its conditions of use in the workplace.


Flash Point:
28 deg C (82 deg F) (closed cup) (4b)

Lower Flammable (Explosive) Limit (LFL/LEL):
1.7% at 51 deg C (6)

Upper Flammable (Explosive) Limit (UFL/UEL):
10.6% at 94 deg C (6)

Autoignition (Ignition) Temperature:
415 deg C (780 deg F) (6); 427 deg C (800 deg F) (4b)

Sensitivity to Mechanical Impact:
Stable material; probably not sensitive.

Sensitivity to Static Charge:
Will not accumulate static charge. The electrical conductivity of alcohols is high. Vapour in the explosive range can probably be ignited by a static charge.

Fire Hazard Summary:
Flammable liquid. Can release vapours that form explosive mixtures with air at, or above, 28 deg C. Vapour is heavier than air and may travel a considerable distance to a source of ignition and flash back to a leak or open container. Can accumulate in confined spaces, resulting in a flammability hazard.

Extinguishing Media:
Dry chemical powder, "alcohol" foam, polymer foam or carbon dioxide. Water may be ineffective because it may not cool isobutyl alcohol below its flash point.(6)

Fire Fighting Instructions:
Shut off flow before attempting to stop the fire. If the leak cannot be stopped, and if there is no risk to the surrounding area, let the fire burn itself out. If the flames are extinguished without stopping the leak, vapours could form explosive mixtures with air and reignite.
Isolate materials not yet involved in the fire and protect personnel. Move containers from fire area if this can be done without risk. Keep cooling streams of water on fire-exposed tanks or containers.
Because of the low flash point, water may be ineffective for fighting fires involving isobutyl alcohol. However, water can be applied as a fine spray to absorb the heat of the fire and to cool exposed containers and materials, and is capable of extinguishing the fire if used under favourable conditions and when hose streams are applied by experienced firefighters trained in fighting all types of flammable liquid fires.
If a leak or spill has not ignited, use water spray to disperse the vapours and to protect personnel attempting to stop a leak. Water spray can be used to dilute spills to nonflammable mixtures and to flush spills away from ignition sources. Solid streams of water may be ineffective and spread material. For 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. Stay away from ends of tanks. Withdraw immediately in case of rising sound from venting safety device or any discolouration of tank due to fire.
Isobutyl alcohol is only slightly hazardous to health. However, as in any fire, a self-contained breathing apparatus (SCBA), pressure-demand, (MSHA/NIOSH approved or equivalent) and full protective equipment (Bunker Gear) should be worn.


NFPA - Health: 2 - Intense or continued (but not chronic) exposure could cause temporary incapacitation or possible residual injury.
NFPA - Flammability: 3 - Liquids and solids that can be ignited under almost all ambient temperature conditions.
NFPA - Instability: 0 - Normally stable, even under fire conditions, and not reactive with water.


Molecular Weight: 74.12

Conversion Factor:
1 ppm = 3.03 mg/m3; 1 mg/m3 = 0.33 ppm at 25 deg C (calc.)

Physical State: Liquid
Melting Point: -108 deg C (-162 deg F) (4a,b)
Boiling Point: 108 deg C (227 deg F) (4a,b)
Relative Density (Specific Gravity): 0.8 at 20 deg C (1) (water = 1)
Solubility in Water: Moderately soluble (9.8 g/100 mL) at 20 deg C (1)
Solubility in Other Liquids: Soluble in all proportions in ethyl alcohol and diethyl ether).(1)
Coefficient of Oil/Water Distribution (Partition Coefficient): Log P(oct) = 0.65; Log P(oct) = 0.83 (5)
pH Value: Not available. Probably neutral.
Vapour Density: 2.6 (air = 1) (6)
Vapour Pressure: Moderate: 1.173 kPa (8.8 mm Hg) at 20 deg C (4a); 1.33 kPa (10 mm Hg) at 25 deg C (4b)
Saturation Vapour Concentration: 11580 ppm at 20 deg C; 13160 ppm at 25 deg C (calc.)
Evaporation Rate: 0.82 (butyl acetate = 1)
Critical Temperature: 265 deg C (509 deg F (4a); 275 deg C (572 deg F) (4b)

Other Physical Properties:
VISCOSITY - DYNAMIC: 4.7 centipoises (4.7 mPa.s) at 15 deg C (4b) 4.0 centipoises (4.0 mPa.s) at 20 deg C (4b)
CRITICAL PRESSURE: 4330 kPa (42.73 atmospheres) (4b)


Normally stable.

Hazardous Polymerization:
Does not occur.

Incompatibility - Materials to Avoid:

NOTE: Chemical reactions that could result in a hazardous situation (e.g. generation of flammable or toxic chemicals, fire or detonation) are listed here. Many of these reactions can be done safely if specific control measures (e.g. cooling of the reaction) are in place. Although not intended to be complete, an overview of important reactions involving common chemicals is provided to assist in the development of safe work practices.

OXIDIZING AGENTS (e.g. peroxides, perchlorates, nitrates) - Increased risk of fire and explosion.
CHROMIUM TRIOXIDE - Butanols are ignited by chromium trioxide, due to vigorous oxidation of the alcohol.

Mixtures or reactions of alcohols with the following materials may cause explosions: barium perchlorate, chlorine, ethylene oxide, hexamethylene diisocyanate and other isocyanates, hydrogen peroxide and sulfuric acid, hypochlorous acid, nitrogen tetroxide, hot perchloric acid, permonosulfuric acid and tri-isobutyl aluminum.(6)

Hazardous Decomposition Products:

Conditions to Avoid:
Static discharge, sparks, heat, open flames and other sources of ignition.

Corrosivity to Metals:
Not corrosive.

Stability and Reactivity Comments:
Isobutyl alcohol will attack some forms of plastics, rubber and coatings.


LD50 (oral, rat): 2460 mg/kg.(7)
LD50 (oral, rabbit): 3000 mg/kg (reported as 41 mmoL/kg) (8)

LD50 (dermal, rabbit): 3400 mg/kg (reported as 4.24 mL/kg).(7)

Eye Irritation:

Application of 0.1 mL of 100%, 30% or 10% isobutyl alcohol caused severe, moderate and mild irritation in rabbits respectively in standard Draize tests.(9) Application of 0.005 or 0.02 mL of undiluted isobutyl alcohol caused severe irritation in rabbits.(7)

Skin Irritation:

Application of 0.01 mL of undiluted isobutyl alcohol produced no reaction in rabbits.(7)

Effects of Short-Term (Acute) Exposure:

Exposure to 10600 ppm (approximately the saturated vapour concentration) for 5 hours resulted in deaths to mice.(10) No rats exposed to 11600 ppm for 2 hours died, while 2 of 6 rats exposed to 8000 ppm for 4 hours died.(7) A concentration of 1818 ppm produced a 50% decrease in the respiratory rate (RD50) in male rats.(16) This concentration is expected to be intolerable for humans. Rats and rabbits were exposed for 4 hours to various concentrations. At 15700 mg/m3 (5180 ppm), there was immediate irritation of the airways. Three days later, symptoms included central nervous system depression, and other effects including a decreased number of lymphocytes in bone marrow, and morphological changes in hepatocytes. At 8000 mg/m3 (2640 ppm), symptoms were similar but less severe. At 1300 mg/m3 (430 ppm) and 670 mg/m3 (220 ppm), there were decreased bone marrow lymphocyte numbers. The irritant threshold was reported to be 270 mg/m3 (90 ppm).(17,18)

A dose of 1400 mg/kg (reported as 19 mmol/kg) caused narcosis (stupor, lethargy) in 50% of rabbits tested.(8) Aspiration (inhalation of fluid) of 0.2 mL of pure or 85% isobutyl alcohol in water caused immediate respiratory failure and cardiac arrest in treated rats.(13)

Effects of Long-Term (Chronic) Exposure:

Mice exposed repeatedly and intermittently by inhalation to 5333 ppm for 9.25 hours for a total of 223 hours (24 exposures) showed no toxic effects. Higher exposure at 6400 ppm, for a series of repeated and intermittent exposures totalling 136 hours, caused narcosis in mice (stupor, lethargy) and mild changes to liver and kidney cells.(10)

Rats were exposed orally to up to 1000 mg/kg/day for 13 weeks. There were no adverse effects on body weight, or clinical or histopathological parameters at 100 or 316 mg/kg. Exposure to 1000 mg/kg/day produced consistently reduced activity in the first week then more sporadically, but generally within a few minutes after dosing for 10 minutes. Incoordination occurred at 1000 mg/kg throughout the study.(23) Male and female rats were administered 0, 1000, 4000 or 16000 ppm (approx. equivalent to 0, 80, 340 or 1450 mg/kg) isobutyl alcohol in drinking water for 3 months. There were no adverse effects noted.(1) Male rats were given a 2M (148 g/L) solution of isobutyl alcohol as the sole drinking source for 2 months; and a 1 M (74 g/L) solution for 4 months and 6 months. Doses ranged from 4800 to 9300 mg/kg/day. All doses caused increased gastrointestinal bleeding. Slight liver effects (decreased liver- to-body weight ratios and overall hepatocyte size) were seen in the rats given the 2M for 2 months. However, the authors believe the liver damage resulted from nutritional deficiencies secondary to the internal bleeding.(20,21)

Malignant tumours developed in 3/19 rats receiving oral doses of 0.2 mL/kg (160 mg/kg) twice weekly for about 71 weeks. No malignant tumours were seen in control animals. Treated animals may also have had severe liver damage and other effects.(11) This study has serious design limitations (dose, number of animals, toxic effects, lack of statistical analysis) and does not meet current standards for carcinogenicity testing.

Teratogenicity, Embryotoxicity and/or Fetotoxicity:
Rats and rabbits were exposed by inhalation to 0, 0.5, 2.5, or 10 mg/L (equivalent to 0, 165, 825 or 3300 ppm) 6 hours/day during days 7 to 19 of pregnancy. Maternal toxicity (slight body weight suppression) was observed at the high dose in rabbits only. No adverse fetal or developmental effects were reported in rats or rabbits.(1)


Selected Bibliography:
(1) Lington, A.W., et al. Alcohols. In: Patty's industrial hygiene and toxicology. Edited by G.D. Clayton, et al. 4th ed. Vol. II, part D. Toxicology. John Wiley & Sons, 1994. p. 2641-2644
(2) Odor thresholds for chemicals with established occupational health standards. American Industrial Hygiene Association, 1989. p. 21, 63
(3) Ruth, J.H. Odor thresholds and irritation levels of several chemical substances: a review. American Industrial Hygiene Association Journal. Vol. 47 (Mar. 1986). p. A142-A151
(4a) Kirk-Othmer encyclopedia of chemical technology. Vol. 4. 3rd ed. John Wiley & Sons, 1978. p. 338-345
(4b) Kirk-Othmer encyclopedia of chemical technology. Vol. 4. 4th ed. John Wiley & Sons, 1992. p. 691-700
(5) Leo, A., et al. Partition coefficients and their uses. Chemical Reviews. Vol. 71, no. 6 (Dec. 1971). p. 525-616
(6) Fire protection guide to hazardous materials. 13th ed. Edited by A.B. Spencer, et al. National Fire Protection Association, 2002. NFPA 325; NFPA 491 (alcohols)
(7) Smyth, H.F., et al. Range-finding toxicity data list V. A.M.A. Archives of Industrial Hygiene and Occupational Medicine. Vol. 10 (1954). p. 61-68
(8) Munch, J.C. Aliphatic alcohols and alkyl esters: narcotic and lethal potencies to tadpoles and to rabbits. IMS: The International Journal of Industrial Medicine and Surgery. Vol. 41, no. 4 (Apr. 1972). p. 31-33
(9) Kennah II, H.F., et al. An objective procedure for quantitating eye irritation based upon changes of corneal thickness. Fundamental and Applied Toxicology. Vol. 12, no. 2 (Feb. 1989). p. 258-268
(10) Weese, H. Comparative studies of the efficacy and toxicity of the vapors of lower aliphatic alcohols. Archiv fuer Experimentelle Pathologie und Pharmakologie. Vol. 135 (1928). p. 118-130 (English translation: NIOSH Control Number: 00134332).
(11) Gibel, W., et al. Experimental investigations of the cancerogenic activities of solvents using propanol-1, 2-methylpropanol-1 and 3- methylbutanol-1 as examples. Archiv. fur Geschwulstforschung. Vol. 45, no. 1 (1975). p. 19-24 (English translation: National Health and Welfare Translation Bureau Number 743281).
(12) Gerarde, H.W., et al. The aspiration hazard and toxicity of a homologous series of alcohols. Archives of Environmental Health. Vol. 13 (Oct. 1966). p. 457-461
(13) Seitz, B. Severe vertigo appearing after handling of butanol and isobutanol. Concerning three cases. Archives des Maladies Professionnelles. Vol. 33 (Jul-Aug 1972). p. 33, 393-395 (English translation: NIOSH Control Number: 00145674).
(14) NIOSH pocket guide to chemical hazards. NIOSH, June 1994. p. 176-177
(15) Forsberg, K., et al. Quick selection guide to chemical protective clothing. 4th ed. Van Nostrand Reinhold, 2002
(16) De Ceaurriz, J.C., et al. Sensory irritation caused by various industrial airborne chemicals. Toxicology Letters. Vol. 9 (1981). p. 137- 143
(17) Health and environmental effects profile for isobutanol. U.S. Environmental Protection Agency (May 1986)
(18) Butanols - four isomers: 1-butanol, 2-butanol, tert-butanol, isobutanol. World Health Organization, International Program on Chemical Safety. Environmental Health Criteria. No. 65 (1987)
(19) Zeiger, E., et al. Salmonella mutagenicity tests: IV. Results from the testing of 300 chemicals. Environmental and Molecular Mutagenesis. Vol. 11 Supplement 12 (1988) p. 1-158
(20) Hillbom, M.E., et al. Effects of chronic ingestion of some lower aliphatic alcohols in rats. Research Communications in Chemical Pathology and Pharmacology. Vol. 9, No. 1 (Sept. 1974). p. 177-180
(21) Hillbom, M.E., et al. Effects of chronic ingestion of some lower alipahatic alcohols in rats. Japanese Journal of Studies on Alcohols. Vol. 9, No. 2 (1974). p. 101-108
(22) Hilscher, H., et al. Toxicity and mutagenicity of individual fused oil components in E.Coli (Translation). Acta Biologica et Medica Germanica. Vol. 23 (1969). p. 843-852
(23) Tompkins, E.C. Toxicity Research Laboratories. Rat oral subchronic toxicity study final report. Compound: Isobutyl alcohol. TRL Study # 032- 002 (1987).
(24) European Communities. Commission Directive 98/98/EC. December 15, 1998
(25) Occupational Safety and Health Administration (OSHA). Organic Vapors. In: OSHA Analytical Methods Manual. Revision Date: Oct. 31, 2001. Available at: <>
(26) National Institute for Occupational Safety and Health (NIOSH). Alcohols II. In: NIOSH Manual of Analytical Methods (NMAM(R)). 4th ed. Edited by M.E. Cassinelli, et al. DHHS (NIOSH) Publication 94-113. Aug. 1994. Available at: <>

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: 1995-05-18

Revision Indicators:
Sampling 1995-08-01
Respiratory guidelines 1995-08-01
EU number 1995-08-01
Sensitivity to static charge 1995-10-01
Handling 1995-10-01
TLV-TWA 1995-10-01
US transport 1998-03-01
Bibliography 2000-04-01
EU Class 2000-04-01
EU Risk 2000-04-01
EU Safety 2000-04-01
EU Comments 2000-04-01
Bibliography 2003-04-15
NFPA (health) 2003-04-15
PEL-TWA final 2003-11-06
PEL final comments 2003-11-06
PEL transitional comments 2003-11-06
Resistance of materials for PPE 2004-03-29
Bibliography 2005-03-14
Passive Sampling Devices 2005-03-14
Sampling/analysis 2005-03-14
Sampling/analysis 2005-03-14

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