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CHEMINFO Record Number: 637
CCOHS Chemical Name: l-Limonene


CAS Registry Number: 5989-54-8
RTECS Number(s): OS8350000
EU EINECS/ELINCS Number: 227-815-6
Chemical Family: Unsaturated alicyclic hydrocarbon / cycloalkene / terpene
Molecular Formula: C10-H16
Structural Formula: CH3-C6H8-C(CH3)=CH2


Appearance and Odour:
Colourless liquid; lemon-like odour

Odour Threshold:
Not available.

Warning Properties:
Information for evaluation not available.

l-Limonene is a natural component of pine oils, mint oils and certain other plants. It is commercially prepared at high purity (97-99%) by extraction and distillation or by synthesis from other terpenes. l-Limonene is one of the chemical forms (isomers) of limonene and is a member of a large family of natural hydrocarbons called terpenes. The other form of limonene is called d-limonene (see CHEMINFO 635). These forms are chemically identical except that their molecular structures are mirror images of each other (optical isomers). Also available as a mixture of the d-and l- forms (see CHEMINFO 636). Commercial forms can also contain other terpenes.

Uses and Occurrences:
Flavour and fragrance ingredient; component of artificial essential oils; synthesis of (+)-carvone. Occurs naturally in essential oils of pine, coniferous trees, certain spices (e.g. peppermint and spearmint) and certain other plants. Minor component of turpentine.


Colourless liquid with lemon-like odour. COMBUSTIBLE LIQUID AND VAPOUR. Vapour is heavier than air and may spread long distances. Liquid can float on water and may possibly travel to distant locations and/or spread fire. SKIN IRRITANT. Causes moderate skin irritation. SKIN SENSITIZER. May cause allergic skin reaction.


Effects of Short-Term (Acute) Exposure

Mist and vapour may cause nose and throat irritation.

Skin Contact:
Liquid can probably cause irritation. Application of a 4% solution in petrolatum, under a patch, to the skin of volunteers did not cause irritation after 48 hours, but the undiluted liquid was a moderate irritant in an animal study.(1) Limonene (isomer not specified) was absorbed through the skin at 100 times the rate of water.(5) However, an animal toxicity value suggests that l-limonene is not very toxic by this route of exposure.

Eye Contact:
l-Limonene is expected to be a mild eye irritant, based on animal information for d-limonene.

Specific human information is not available. Five volunteers who ingested 20 g of the closely related chemical, d-limonene, experienced diarrhea and a temporary increase in protein in the urine (proteinurea).(7) This information, in addition to the low toxicity value in an animal test, suggests that l-limonene is not very toxic by ingestion.

Effects of Long-Term (Chronic) Exposure

Skin Sensitization:
l-Limonene is an occupational skin sensitizer. Repeated or prolonged skin contact can cause an allergic skin response (redness, swelling, itching). The allergic response is caused by oxidation products of l-limonene, which are formed upon exposure to air. l-Limonene of very high purity is not expected to produce an allergic response.
A 4% solution of l-limonene did not cause an allergic skin response in any of 23 volunteers tested.(1) Seven of 67 people who had an allergic skin response to turpentine tested positive to 1% l-limonene.(2) The closely related chemical, d-limonene, can cause sensitization.

Specific information is not available, but animal studies with the closely related chemical, d-limonene, suggest that repeated ingestion of large quantities may cause permanent kidney damage (see the CHEMINFO review of d-limonene).


No human or animal information available for l-limonene. The closely related chemical, d-limonene, has caused kidney tumours in male rats following repeated ingestion (see CHEMINFO review for d-limonene). The mechanisms by which d-limonene causes increased tumours in male rats is not considered relevant to humans. The International Agency for Research on Cancer (IARC) has determined that d-limonene is not classifiable as to its carcinogenicity to humans (Group 3).(11)

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 no listing for 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 available. There is limited evidence that d-limonene can cause developmental abnormalities when fed to animals at doses that cause maternal toxicity.

Reproductive Toxicity:
No human or animal information available. Reports of reproductive toxicity in animals following ingestion of high doses of d-limonene could not be verified (see CHEMINFO 635).

There is no human or animal information available. The mixture of isomers, d,l-limonene, and the closely related chemical, d-limonene, were negative in different mutagenicity tests.

Toxicologically Synergistic Materials:
A related chemical, d-limonene, increased the skin absorption of a drug in one study.

Potential for Accumulation:
Specific information is not available, but in humans d-limonene was excreted within 2-3 days following ingestion, mainly in the urine.(8)


If symptoms are experienced, remove source of contamination or move victim to fresh air. Obtain medical advice.

Skin Contact:
Avoid direct contact. Wear chemical protective clothing, if necessary. As quickly as possible, remove contaminated clothing, shoes and leather goods (e.g. watchbands, belts). Quickly and gently blot or brush away excess chemical. Immediately wash gently and thoroughly with lukewarm, gently flowing water and non-abrasive soap for 15-20 minutes. Immediately obtain medical attention. Completely decontaminate clothing, shoes and leather goods before re-use or discard.

Eye Contact:
Avoid direct contact. Wear chemical protective gloves, if necessary. Quickly and gently blot or brush chemical off the face. Immediately flush the contaminated eye(s) with lukewarm, gently flowing water for 5 minutes, while holding the eyelid(s) open. Obtain medical advice.

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. If vomiting occurs naturally, have victim rinse mouth with water again. Immediately obtain medical attention.

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:
48 deg C (118 deg C) (closed cup) (3)

Lower Flammable (Explosive) Limit (LFL/LEL):
0.7% at 150 deg C [Dipentene(limonene)] (9)

Upper Flammable (Explosive) Limit (UFL/UEL):
6.1% at 150 deg C [Dipentene(limonene)]

Autoignition (Ignition) Temperature:
237 deg C (458 deg F) (Dipentene(limonene)]

Sensitivity to Mechanical Impact:
Probably not sensitive

Sensitivity to Static Charge:
May accumulate static charge by flow or agitation. Mixtures of l-limonene vapour and air at concentrations in the flammable range may be ignited by a static spark. Information on the minimum ignition energy is not available.

Fire Hazard Summary:
Can form explosive mixtures at, or above 48 deg C. Liquid can float on water and may possibly travel to distant locations and/or spread fire.

Extinguishing Media:
Dry chemical powder, foam, polymer foam, water spray or fog.

Fire Fighting Instructions:
l-Limonene is insoluble and floats on top of water. Water spray may be used to extinguish fires, because l-limonene can be cooled below its flash point. Water spray can be used to absorb heat, keep containers cool and protect exposed material. 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 may be used to flush spills away from exposures.

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: 2 - Intense or continued (but not chronic) exposure could cause temporary incapacitation or possible residual injury. (dipentene (limonene)).
NFPA - Flammability: 2 - Must be moderately heated or exposed to relatively high ambient temperatures before ignition can occur. (dipentene (limonene)).
NFPA - Instability: 0 - Normally stable, even under fire conditions, and not reactive with water. (dipentene (limonene)).


Molecular Weight: 136.24

Conversion Factor:
1 ppm = 5.56 mg/m3; 1 mg/m3 = 0.179 ppm at 25 deg C

Physical State: Liquid
Melting Point: Not available. (-96.5 deg C (-140 deg F) for d,l-limonene)
Boiling Point: 176-177 deg C (349-354 deg F)
Relative Density (Specific Gravity): 0.84 at 20 deg C (water = 1)
Solubility in Water: Insoluble
Solubility in Other Liquids: Soluble in alcohol, ether
Coefficient of Oil/Water Distribution (Partition Coefficient): Not available
pH Value: Not applicable
Vapour Density: 4.7 (air = 1)
Vapour Pressure: Less than 3 mm Hg (0.39 kPa) at 14 deg C (3)
Saturation Vapour Concentration: Less than 4000 ppm at 14 deg C (calculated)
Evaporation Rate: Not available

Other Physical Properties:
SPECIFIC OPTICAL ROTATION: -101.3 degrees at 19.5 deg C


Normally stable. Can slowly oxidize to form a film in the presence of air.(6)

Hazardous Polymerization:
Polymerization is not hazardous. May polymerize slowly in the presence of air.

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 - Increased risk of fire and explosion.
IODINE PENTAFLUORIDE AND TETRAFLUOROETHYLENE - Iodine pentafluoride reacted with limonene in a cylinder made of tetrafluoroethylene causing deflagration of the cylinder material.(9)

Hazardous Decomposition Products:
Information not available

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

Corrosivity to Metals:
Not corrosive


LD50 (oral, rat): Greater than 5 g/kg (1)

LD50 (dermal, rabbit): Greater than 5 g/kg (1)

Skin Irritation:

Application of undiluted l-limonene, under a covering, to intact or abraded skin caused moderate irritation in rabbits after 24 hours.(1)


Selected Bibliography:
(1) l-Limonene. Monographs on fragrance raw materials : special issue IV. Food and Cosmetics Toxicology. Vol. 16, Supplement 1 (Dec. 1978). p. 809
(2) Romaguera, C., et al. Turpentine sensitization. Contact Dermatitis. Vol. 14, no. 3 (1986). p. 197
(3) The Sigma-Aldrich library of chemical safety data. Edition II. Vol. 1 (A-L). Sigma-Aldrich, 1988. p. 2127B
(4) Forsberg, K., et al. Quick selection guide to chemical protective clothing. 4th ed. Van Nostrand Reinhold, 2002
(5) Patty's industrial hygiene and toxicology. 3rd rev. ed. Vol. 2B. John Wiley & Sons, 1981. p. 3232, 3236-3238, 3249-3250
(6) Hawley's condensed chemical dictionary. 11th ed. Van Nostrand Reinhold, 1987. p. 701
(7) Igimi, H., et al. The use of d-limonene preparation as a dissolving agent of gallstones. Digestive Diseases. Vol. 21, no. 11 (Nov. 1976). p. 926-939
(8) Jameson, C.W. NTP technical report on the toxicology and carcinogenesis studies of d-limonene (Cas no. 5989-27-5) in F344/N rats and B6C3F1 mice (Gavage studies). (NTP TR 347) National Institutes of Health. 1990
(9) Fire protection guide to hazardous materials. 13th ed. Edited by A.B. Spencer, et al. National Fire Protection Association, 2002. NFPA 325; NFPA 491
(10) Workplace environmental exposure level guide. AIHA Journal. Vol. 56, no. 2 1995. p. 202
(11) International Agency for Research on Cancer (IARC). IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Vol. 73. Some chemicals that cause tumours of the kidney or urinary bladder in rodents and some other substances. World Health Organization, 1999
(12) European Communities. Commission Directive 98/73/EC. Sept. 18, 1998

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: 1992-09-14

Revision Indicators:
Fire fighting instructions 1994-01-01
Fire hazard comments 1994-01-01
Conditions to avoid 1994-01-01
Trans PEL-TWA 1993-04-01
TDG 1994-02-01
Sensitivity to static charge 1995-10-01
Synergism 1996-06-01
US Transport 1996-06-01
Sampling 1996-06-01
EU Risk 1999-12-01
EU Safety 1999-12-01
EU Comments 1999-12-01
Carcinogenicity 2000-06-01
Bibliography 2003-04-14
NFPA (health) 2003-04-14
Resistance of materials for PPE 2004-03-29
EU classification 2005-02-06
Long-term exposure 2005-10-18
Short-term skin contact 2005-10-18
Short-term inhalation 2005-10-18
WHMIS detailed classification 2005-10-18
WHMIS health effects 2005-10-18
Emergency overview 2005-10-18
First aid skin 2005-10-18
First aid eye 2005-10-18
Handling 2005-10-19

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