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CHEMINFO Record Number: 636
CCOHS Chemical Name: d,l-Limonene

Inactive limonene
Racemic limonene

CAS Registry Number: 138-86-3
UN/NA Number(s): 2052
RTECS Number(s): OS8100000
EU EINECS/ELINCS Number: 205-341-0
Chemical Family: Unsaturated alicyclic hydrocarbon / cycloalkene / terpene
Molecular Formula: C10-H16


Appearance and Odour:
Colourless liquid; lemon-like odour.

Odour Threshold:
Not available

Warning Properties:
Information for evaluation not available

d,l-Limonene (dipentene) is a mixture of two chemical forms (isomers), d- limonene (5989-27-5) (CHEMINFO 635) and l-limonene (5989-54-8) (CHEMINFO 637). These forms are chemically identical except that their molecular structures are mirror images of one another (optical isomers). Commercial mixtures can also contain other terpenes and related compounds such as p- cumene.

Uses and Occurrences:
Solvent for oleoresinous products, rosin, ester gum, alkyd resins, waxes, rubber; in rubber compounding and reclaiming; wetting agent and dispersing agent for oils, resins, pigments, driers; printing inks; flavour and fragrance ingredient; floor waxes and furniture polishes. Occurs naturally in essential oils of many 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 20% d,l-limonene, under a patch, to the skin of volunteers did not cause irritation after 48 hours (3), but the individual isomers, d-limonene and l-limonene, are moderately irritating in animal tests when applied undiluted. Limonene (isomer not specified) was absorbed through the skin at 100 times the rate of water.(5) However, d,l-limonene was not very toxic when applied to the skin in an animal test.

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

Ingestion of 20 g of d-limonene caused diarrhea and a temporary increase in protein in the urine (proteinurea) in 5 male volunteers.(9) Specific human information is not available for d,l-limonene, but the low acute toxicity in an animal test suggests that d,l-limonene is not very toxic by ingestion.

Effects of Long-Term (Chronic) Exposure

Skin Sensitization:
d,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 d,l-limonene, which are formed upon exposure to air. d,l-Limonene of very high purity is not expected to produce an allergic response.
A 20% solution of d,l-limonene did not cause an allergic skin response in any of 25 volunteers tested.(3) In 3 cases of allergic contact dermatitis, d,l-limonene, which was present at 5% in a product used in each case, was thought to be responsible.(4) The individual isomers, d-limonene and l-limonene, can cause skin sensitization.

REPEATED INGESTION: Low levels of d-limonene in the diet (about 100 ppm) have not been reported to cause adverse effects in humans. Animal tests suggest that repeated ingestion of large quantities of d-limonene may cause kidney damage (refer to the CHEMINFO review of d-limonene).


There is no specific human or animal information available for d,l-limonene. d-Limonene has caused kidney tumours in male rats following repeated ingestion. The mechanism by which d-limonene causes increased tumours in male rats is not considered relevant to humans (see the CHEMINFO review of d-limonene). The International Agency for Research on Cancer (IARC) has concluded that d-limonene is not classifiable as to its carcinogenicity to humans.(14)

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 information. Limited evidence of developmental abnormalities in animals exposed to d-limonene at doses that caused maternal toxicity (see CHEMINFO 635).

Reproductive Toxicity:
No human information. Reports of reproductive toxicity in animals following ingestion of d-limonene could not be verified.

There is no human information. Negative results have been obtained in a study using live animals, and a route of exposure that is not considered relevant to occupational exposures (intraperitoneal injection).

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 is excreted within 2-3 days following ingestion, mainly in the urine.(10)


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:
45 deg C (113 deg F) (closed cup) (1)

Lower Flammable (Explosive) Limit (LFL/LEL):
0.7% at 150 deg C (1)

Upper Flammable (Explosive) Limit (UFL/UEL):
6.1% at 150 deg C (1)

Autoignition (Ignition) Temperature:
237 deg C (458 deg F) (1)

Sensitivity to Mechanical Impact:
Not available. Probably not sensitive.

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

Fire Hazard Summary:
Combustible liquid. Can form explosion mixtures at, or above 45 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:
Water spray may be used to extinguish fires, because d,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 way 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.
NFPA - Flammability: 2 - Must be moderately heated or exposed to relatively high ambient temperatures before ignition can occur.
NFPA - Instability: 0 - Normally stable, even under fire conditions, and not reactive with water.


Molecular Weight: 136.24

Conversion Factor:
1 ppm = 5.56 mg/m3; 1 mg/m3 = 0.18 ppm at 25 deg C

Physical State: Liquid
Melting Point: -95.5 deg C (-140 deg F)
Boiling Point: 170 deg C (339 deg F) (1)
Relative Density (Specific Gravity): 0.84 (water = 1)
Solubility in Water: Insoluble
Solubility in Other Liquids: Soluble in alcohol, ether.
Coefficient of Oil/Water Distribution (Partition Coefficient): Log P(oct): 4.57 (experimental) (15)
pH Value: Not applicable
Vapour Density: 4.70 (air = 1)
Vapour Pressure: 2.1 mm Hg (0.280 kPa) at 20 deg C (11)
Saturation Vapour Concentration: 2800 ppm at 20 deg C (calc.)
Evaporation Rate: Not available
Critical Temperature: Not available


Normally stable. Can slowly oxidize to form a film in the presence of air.(7)

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.(1)

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): 5.3 g/kg (3)

LD50 (dermal, rabbit): Greater than 5 g/kg (3)

Not mutagenic in bacteria (Ames test). Negative in the mouse spot test, in which d,l-limonene (215 mg/kg) was injected into the major body cavity on days 9, 10 and 11 of pregnancy; the offspring were then examined for a specific gene mutation in somatic cells.(6)


Selected Bibliography:
(1) Fire protection guide to hazardous materials. 13th ed. Edited by A.B. Spencer, et al. National Fire Protection Association, 2002. NFPA 325; NFPA 491
(2) Forsberg, K., et al. Quick selection guide to chemical protective clothing. 4th ed. Van Nostrand Reinhold, 2002
(3) Opdyke, D.L.J. Monographs on fragrance raw materials. Food and Cosmetics Toxicology. Vol. 12 (1974). p. 703-704
(4) Rycroft, R.J.G. Allergic contact dermatitis from dipentene in honing oil. Contact Dermatitis. Vol. 6, no. 5 (1980). p. 325-329
(5) Patty's industrial hygiene and toxicology. 3rd rev. ed. Vol. 2B. John Wiley & Sons, 1981. p. 3231-3232, 3236-3238, 3249-3250
(6) Styles, J.A., et al. The mouse spot test : evaluation of its performance in identifying chemical mutagens and carcinogens. Mutation Research. Vol. 154, no. 3 (Nov. 1985). p. 183-204
(7) Hawley's condensed chemical dictionary. 11th ed. Van Nostrand Reinhold, 1987. p. 701
(8) The Merck index: an encyclopedia of chemicals, drugs, and biologicals. 10th ed. Merck, 1983. p. 788
(9) 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
(10) 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) (NTPTR347). National Institutes of Health, 1990
(11) Handling chemicals safely. 2nd ed. Dutch Association of Safety Experts, 1980. p. 591
(12) Workplace environmental exposure level guide. AIHA Journal. Vol. 56, no. 2, 1995. p. 202
(13) European Communities. Commission Directive 98/73/EC. September 18, 1998
(14) 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
(15) Syracuse Research Corporation. Interactive LogKow (KowWin) Database Demo. Date unknown. 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: 1992-09-14

Revision Indicators:
Fire hazard comments 1994-01-01
Fire fighting instructions 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
Handling 1995-01-01
Toxicological Synergism 1996-06-01
Sampling 1996-06-01
Protective equipment 1996-06-01
US transport 1998-02-01
EU Risk 1999-12-01
EU Safety 1999-12-01
EU Comments 1999-12-01
Carcinogenicity 2000-06-01
Mutagenicity 2000-06-01
Bibliography 2003-04-14
Boiling point 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 inhalation 2005-10-18
Short-term eye contact 2005-10-18
WHMIS detailed classification 2005-10-18
Emergency overview 2005-10-18
First aid skin 2005-10-18
First aid eye 2005-10-18
WHMIS health effects 2005-10-18
Handling 2005-10-19
Partition coefficient 2005-12-19
Bibliography 2005-12-19

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