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CHEMINFO Record Number: 255
CCOHS Chemical Name: n-Heptane

Heptyl hydride

Chemical Name French: Heptane normal
Chemical Name Spanish: n-Heptano

Trade Name(s):
Skellysolve C

CAS Registry Number: 142-82-5
UN/NA Number(s): 1206
RTECS Number(s): MI7700000
EU EINECS/ELINCS Number: 205-563-8
Chemical Family: Saturated aliphatic hydrocarbon / alkane / n-alkane / heptane isomer
Molecular Formula: C7-H16
Structural Formula: CH3-(CH2)5-CH3


Appearance and Odour:
Colourless liquid with a gasoline-like odour.(2)

Odour Threshold:
230 ppm (detection); 330 ppm (recognition) (5)

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

n-Heptane is one of the chemical forms (isomers) of heptane (C7-H16). It has many similarities (properties and hazards) to other heptanes. The information presented in this CHEMINFO record is given for n-heptane, where available. Otherwise, information is given for other isomers or heptanes in general.

Uses and Occurrences:
As a solvent in glues, varnishes, cements and inks; extracting natural oils and fats; as a standard in gasoline octane ratings; as a replacement for n-hexane. Occurs as a major ingredient in gasoline and aviation fuel and in petroleum solvents such as petroleum naphtha and rubber solvent.


Colourless liquid, gasoline-like odour. FLAMMABLE LIQUID AND VAPOUR. Can accumulate static charge. Vapour is heavier than air and may spread long distances. Distant ignition and flash back are possible. Liquid can float on water and may travel to distant locations or spread fire. Mild central nervous system depressant. High vapour concentrations may cause headache, nausea, dizziness, drowsiness, incoordination, and unconsciousness. Aspiration hazard. Swallowing or vomiting of the liquid may result in aspiration into the lungs. SKIN IRRITANT. Causes severe skin irritation.


Effects of Short-Term (Acute) Exposure

The main effect of short-term inhalation exposure is depression of the central nervous system. The effects reported in studies with volunteers at 5000 ppm were marked dizziness/giddiness (at 4 minutes); incoordination (at 7 minutes); hilarity or a state of stupor (at 15 minutes) that persisted for 30 minutes after exposure. Subjects reported reduced appetite, slight nausea and a gasoline-like taste that persisted for several hours after exposure. Lower exposures produced only slight dizziness (1000 ppm for 6 minutes or 2000 ppm for 4 minutes).(4) The fatal concentration has been reported to be 16000 ppm.(1) Mucous membrane irritation may occur at high vapour concentrations.(4)

Skin Contact:
n-Heptane is a moderate to severe skin irritant, based on human information and comparison to other aliphatic hydrocarbons.(21) Application of liquid heptane to the forearms of 5 volunteers for 1 hour lead to redness, swelling and a painful sensation in the skin. The pain generally subsided 2 hours after contact was discontinued. A 5-hour application to the upper thigh caused blister formation.(4,9)
Harmful effects are not expected to occur by skin absorption.

Eye Contact:
Based on a report of skin irritation, eye contact with the liquid may result in irritation and pain. Concentrated vapour may cause slight irritation. However, during exposure to 5000 ppm for 4 minutes there were no complaints of eye irritation.(4) There is no human or animal information available.

Animal toxicity information indicates that n-heptane has very low toxicity if ingested. Ingestion of extremely large doses may cause nausea, vomiting, headache and other symptoms of central nervous system depression, as described for "Inhalation" above.
If n-heptane is aspirated into the lungs following ingestion or vomiting, potentially fatal lung damage (pulmonary edema) can result. Based on its physical properties, n-heptane can be easily aspirated.
Ingestion is not a typical route of occupational exposure.

Effects of Long-Term (Chronic) Exposure

No effects following long-term exposure have been reported in humans.

SKIN: The liquid is a defatting agent and prolonged or repeated contact can cause irritation and dermatitis (inflammation, reddening and swelling).

EFFECTS ON NERVOUS SYSTEM: Nerve damage of the extremities, such as the hands and feet (peripheral neuropathy) has been reported in workers exposed to petroleum solvents containing mixtures of chemicals including heptane.(1,4,15) The nervous system effects of the related chemical, n-hexane, have been well established and occur through a metabolite (2,5-hexanedione).(16) Studies have shown that the main metabolite of n-heptane in humans is 2-heptanol and that only a small amount of a metabolic neurotoxin (2,5-heptanedione) is present or is undetectable.(14) While it is not possible to rule out that neurotoxic effects may occur from n- heptane exposure, they are not expected from occupational exposure.

EFFECTS ON BLOOD: Long-term exposure of rubber tire workers to a solvent mixture which included heptane caused some slight blood disorders.(4) No conclusions can be drawn from this report because of the combined exposure.


There is no human or animal information available.

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:
There is no human or animal information available.

Reproductive Toxicity:
There is no human or animal information available.

There is no information available.

Toxicologically Synergistic Materials:
There is no information available.

Potential for Accumulation:
Unlikely to accumulate. n-Heptane is readily metabolized and excreted.(4)


This product is flammable. Take proper precautions (e.g. remove any sources of ignition). Remove source of contamination or move victim to fresh air. If breathing has stopped, trained personnel should begin artificial respiration or, if the heart has stopped, cardiopulmonary resuscitation (CPR) immediately. Obtain medical attention immediately.

Skin Contact:
Remove contaminated clothing, shoes and leather goods (e.g. watchbands, belts). Gently blot or brush away excess chemical quickly. Wash gently and thoroughly with water and non-abrasive soap for at least 20 minutes or until the chemical is removed. Obtain medical attention immediately. Completely decontaminate clothing, shoes and leather goods before re-use or discard.

Eye Contact:
Quickly and gently blot or brush away excess chemical. Immediately flush the contaminated eye(s) with lukewarm, gently flowing water for 5 minutes or until the chemical is removed, while holding the eyelid(s) open. Obtain medical advice immediately.

Never give anything my mouth if victim is rapidly losing consciousness, is unconscious or convulsing. DO NOT INDUCE VOMITING. Have victim drink 240 to 300 mL (8 to 10 oz.) of water. If vomiting occurs naturally, have victim lean forward to reduce risk of aspiration. Repeat administration of water. Obtain medical attention immediately.

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.
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:
-4 deg C (25 deg F) (closed cup) (2): -1 deg C (30 deg C) (closed cup) (17)

Lower Flammable (Explosive) Limit (LFL/LEL):
1.05% (2)

Upper Flammable (Explosive) Limit (UFL/UEL):
6.7% (2)

Autoignition (Ignition) Temperature:
204 deg C (399 deg F) (11)

Sensitivity to Mechanical Impact:
Probably not sensitive. Stable material.

Sensitivity to Static Charge:
n-Heptane can accumulate static charge by flow or agitation due its very low electrical conductivity (6.6 pS/m).(18) Vapour can be ignited readily by static discharge of sufficient energy. Minimum ignition energy: 0.24 millijoules (18)

Fire Hazard Summary:
Flammable liquid. Can release vapours that can form flammable or explosive mixtures with air at, or above -4 deg C. The 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. Liquid can float on water and may travel to distant locations and/or spread fire. Can accumulate in confined spaces resulting in a flammability and toxicity hazard. During a fire, irritating/toxic gases may be generated. Containers may explode in the heat of the fire.

Extinguishing Media:
Carbon dioxide, dry chemical powder, alcohol foam or polymer foam.(17) Water may be ineffective because it will not cool n-heptane below its flash point. Fire fighting foams are the extinguishing agent of choice for most flammable liquid fires.

Fire Fighting Instructions:
Evacuate area and fight fire from a safe distance or protected location. Approach fire from upwind to avoid hazardous vapours and toxic decomposition products.
Stop leak 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.
Water can extinguish 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.
Containers may rupture in the heat of the fire. Isolate materials not yet involved in the fire and protect personnel. Move containers from fire area if this can be done without risk. Otherwise, fire-exposed containers or tanks should be cooled by application of hose streams and this should begin as soon as possible (within the first several minutes) and should concentrate on any unwetted portions of the container. If this is not possible, use unmanned monitor nozzles and immediately evacuate the area.
If a leak or spill has not ignited, use water spray in large quantities to disperse the vapours, 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.
Firefighters may enter the area if positive pressure self-contained breathing apparatus (MSHA/NIOSH approved or equivalent) and full Bunker Gear is worn.


NFPA - Health: 1 - Exposure would cause significant irritation, but only minor residual injury.
NFPA - Flammability: 3 - Liquids and solids that can be ignited under almost all ambient temperature conditions.
NFPA - Instability: Not assigned.


Molecular Weight: 100.2

Conversion Factor:
1 ppm = 4.09 mg/m3; 1 mg/m3 = 0.245 ppm at 25 deg C (calculated)

Physical State: Liquid
Melting Point: -91 deg C (-132 deg F) (4,17)
Boiling Point: 98 deg C (209 deg F) (4,17)
Relative Density (Specific Gravity): 0.684 at 20 deg C (3); 0.688 at 25 deg C (4) (water = 1)
Solubility in Water: Practically insoluble (0.0003%) (2)
Solubility in Other Liquids: Very soluble in ethanol and diethyl ether (4): soluble in most organic solvents.
Coefficient of Oil/Water Distribution (Partition Coefficient): Log P(oct) = 4.66 (4)
pH Value: Not applicable
Vapour Density: 3.52 (air = 1) (4)
Vapour Pressure: 5.3 kPa (40 mm Hg) at 22.3 deg C (2,4)
Saturation Vapour Concentration: 52640 ppm (5.26%) at 22.3 deg C (calculated)
Evaporation Rate: Not available
Critical Temperature: 267 deg C (513 deg F)

Other Physical Properties:
VISCOSITY-DYNAMIC: 0.409 mPa.s (0.40-9 centipoises) at 20 deg C (19)
VISCOSITY-KINEMATIC: 0.598 mm2/s (0.598 centistokes) at 20 deg C (calculated)


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.

STRONG OXIDIZING AGENTS (e.g. peroxides, nitrates and perchlorates) - may react violently. Increased risk of fire and explosion.(2,17)

Hazardous Decomposition Products:

Conditions to Avoid:
Heat, open flames, static discharge, sparks and other ignition sources

Corrosivity to Metals:
Not corrosive


LC50 (rat): approximately 25000 ppm (4-hour exposure); cited as 103 g/m3 (4-hour exposure) (6, unconfirmed)

LD50 (oral, rat): Greater than 15000 mg/kg (4, unconfirmed)

Effects of Short-Term (Acute) Exposure:

The primary effect of inhaling n-heptane is depression of the central nervous system. The order of symptoms shown by experimental animals with increasing dosage is irritation, irregular respiration, prostration, coma, convulsions and death resulting from respiratory arrest.(1,4,10) Mice exposed to 8000 ppm for 5 minutes showed irritation, irregular respiration and unconsciousness.(10) At 10000-15000 ppm there were signs of narcosis within 30 to 50 minutes; 15000-20000 ppm for 30 to 60 minutes caused convulsions and death.(1) Respiratory arrest occurred in 3 of 4 mice within 3 minutes at 48000 ppm.(1,10)

Effects of Long-Term (Chronic) Exposure:

No major toxic effects have been reported in long-term inhalation studies. No toxic effects were seen in rats exposed to 400 or 3000 ppm for 26 weeks. Some changes in liver enzymes were noted but not in blood parameters.(4) n-Heptane has been shown to cause some hearing loss in rats exposed to 4000 ppm for 28 days. There was a significant increase in the auditory threshold of the mid-range frequencies (8 and 16 kHz). These effects were not seen in the low exposure group (800 ppm).(12) n-Heptane has not shown the neurological effects found with similar exposures to n-hexane. Rats exposed to n-heptane at 3000 ppm for 16 weeks showed no evidence of peripheral nerve damage.(4) Similar negative neurological findings were reported in rats exposed to concentrations of 1500 ppm for 30 weeks or 3000 ppm for 26 weeks.(4) Metabolic studies with n-heptane with single 6-hour exposures of rats to 1800 ppm (14) or 2000 ppm (13) have shown that a neurotoxic metabolite (2,5-heptanedione) is present in urine of exposed animals. However it is a minor metabolite present in very small amounts (<1% of total metabolites).(13,14)


Selected Bibliography:
(1) Heptane (n-heptane). In: Documentation of the threshold limit values and biological exposure indices. 6th ed. American Conference of Government Industrial Hygienists, 1991. p. 734-735
(2) NIOSH pocket guide to chemical hazards. National Institute for Occupational Safety and Health, June 1994. p. 156-157
(3) Cavender, F. Aliphatic hydrocarbons. In: Patty's industrial hygiene and toxicology. 4th ed. Vol. II. Toxicology. Part B. Edited by G.D. Clayton et al. John Wiley and Sons, 1994. p. 1223, 1226-1227, 1235-1236.
(4) Low, L.K., et al. n-Heptane. In: Ethel Browning's toxicity and metabolism of industrial solvents. Vol. 1: Hydrocarbons. 2nd ed. Elsevier Science Publishers, 1987. p. 297-306
(5) Odor thresholds for chemicals with established occupational health standards. American Industrial Hygiene Association, 1989. p. 20, 60-61
(6) RTECS record for heptane. Last updated: 9601
(7) HSDB record for heptane. Last revision date: 1996-01-18.
(8) Forsberg, K., et al. Quick selection guide to chemical protective clothing. 4th ed. Van Nostrand Reinhold, 2002
(9) Oettel, H. Effect of organic liquids on the skin. Archiv. fuer Experimentelle Pathologie. Vol. 83 (1936). p. 641-696
(10) Swann, H.E., et al. Acute inhalation toxicology of volatile hydrocarbons. American Industrial Hygiene Association Journal. Vol. 35, no.7 (Sept. 1974). p. 511-518
(11) Fire protection guide to hazardous materials. 13th ed. Edited by A.B. Spencer, et al. National Fire Protection Association, 2002. NFPA 325
(13) Bahima, J., et al. Identification of volatile metabolites of inhaled n- heptane in rat urine. Toxicology and Applied Pharmacology. Vol. 76 (1984). p. 473-482
(14) Perbellini, L., et al. Identification of the n-heptane metabolites in rat and human urine. Archives of Toxicology. Vol. 58, no.4 (1986). p. 229- 234
(15) Valentini, F., et al. Does n-heptane cause peripheral neurotoxicity? A case report in a shoemaker. Occupational Medicine. Vol. 44 (1994). p. 102- 104
(16) Perbellini, L., et al. Identification of the metabolites of n-hexane, cyclohexane, and their isomers in men's urine. Toxicology and applied pharmacology. Vol. 53 (1980). p. 220-229
(17) The Sigma-Aldrich library of chemical safety data. Ed. II. Vol. 1. Sigma-Aldrich Corporation, 1988. p. 1821C
(18) Chemical safety sheets: working safely with hazardous chemicals. Kluwer Academic Publishers, 1991. p. 454
(19) Weast, R.C., ed. Handbook of chemistry and physics. 66th ed. CRC Press, 1985-1986. p. F-40
(20) European Communities. Commission Directive 98/98/EC. Dec. 15, 1998
(21) Jacobs, G., et al. Proposal of limit concentrations for skin irritation within the context of the new EEC Directive on the Classification and Labeling of Preparations. Regulatory Toxicology and Pharmacology. Vol. 7, no. 4 (1987). p. 370-378
(22) Occupational Safety and Health Administration (OSHA). Organic Vapors. In: OSHA Analytical Methods Manual. Revision Date: Oct. 31, 2001. Available at: <>
(23) National Institute for Occupational Safety and Health (NIOSH). Hydrocarbons, BP 36-216 deg C. 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: <>
(24) National Institute for Occupational Safety and Health (NIOSH). Volatile Organic Compounds (Screening). 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: 1997-05-22

Revision Indicators:
US transport 1998-02-01
TLV comments 1998-08-01
EU Class 2000-04-01
EU Risk 2000-04-01
EU Safety 2000-04-01
EU Comments 2000-04-01
Short-term skin contact 2003-01-14
OSHA hazcom 2003-01-14
Emergency overview 2003-01-14
First aid skin 2003-01-14
Storage 2003-01-14
NFPA (reactivity) 2003-04-16
PEL transitional comments 2003-12-04
PEL-TWA final 2003-12-04
PEL-STEL final 2003-12-04
Resistance of materials for PPE 2004-04-05
Bibliography 2004-04-05
Bibliography 2005-04-07
Passive Sampling Devices 2005-04-07
Sampling/analysis 2005-04-07

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