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Chemical Sampling Information (CSI)
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General Description

Synonyms: 1-methyl-4-(1-methylethenyl)cyclohexene, (R); l-Limonene; d-Limonene; dl-Limonene; Dipentene; Acintene DP; Cinene; Dipanol; Unitene; 1-methyl-4-isopropentyl-1-cyclohexene

OSHA IMIS Code Number: L129

Chemical Abstracts Service (CAS) Registry Number: 138-86-3

Other Chemical Abstracts Service (CAS) Registry Numbers: 5989-27-5 (d-Limonene)

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: GW6360000

Chemical Description and Physical Properties:

colorless to very pale yellow flammable liquid; floats on water
molecular weight: 136.23
molecular formula: C10H16
boiling point: 177°C
melting point: -96.9°C
flash point: 43°C

Health Factors

Potential Symptoms: Irritation of eyes, nose, throat, skin; allergic contact dermatitis

Health Effects: Irritation-Eyes, Nose, Throat, Skin---Mild (HE16); Skin sensitization--- Dermatitis (HE3)

Affected Organs: Eyes, skin

Notes:

  1. Limonene is on FDA's list of synthetic flavoring substances and adjuvants that are Generally Recognized as Safe (GRAS) (21 CFR 182.60).
  2. Oxidation products of limonene that form during handling and storage, rather than limonene itself, are the mediators of irritation and sensitization.
  3. Although chronic oral administration of d-limonene to rats caused kidney damage and kidney tumors in the males, this effect is thought to have no human relevance (IARC Group 3).
  4. Metabolized by several hepatic enzymes (CYP2C8, CYP2C9, CYP2C18, CYP2C19, CYP3A4) to carveols (6-hydroxylation) and perillyl alcohols (7-hydroxylation), with CYP2C9 and CYP2C19 showing the greatest activities in human liver microsomes.

Literature Basis:

  • International Chemical Safety Cards (WHO/IPCS/ILO): D-Limonene.
  • National Industrial Chemicals Notification and Assessment Scheme (Australia): Limonene. Priority Existing Chemical Assessment Report No. 22, (May) 2002, 130 pp.
  • NIOSH Registry of Toxic Effects of Chemical Substances, RTECS #: GW6360000: Cyclohexene, 1-methyl-4-(1-methylethenyl)-, (R)-.
  • Karlberg, A.T. and Dooms-Goossens, A.: Contact allergy to oxidized d-limonene among dermatitis patients. Contact Dermatitis 36(40: 201-206, 1997.
  • Kleno, J. and Wolkoff, P.: Changes in eye blink frequency as a measure of trigeminal stimulation by exposure to limonene oxidation products, isoprene oxidation products and nitrate radicals. Int. Arch. Occup. Environ. Med. 77(4): 235-243, 2004.
  • Matura, M., et al.: Oxidized citrus oil (R-limonene): a frequent skin sensitizer in Europe. J. Am. Acad. Dermatol. 47(5): 709-714, 2002.
  • Miyazawa, M., Shindo, M. and Shimada, T.: Metabolism of (+)- and (-)-limonenes to respective carveols and perillyl alcohols by CYP2C9 and CYP2C19 in human liver microsomes. Drug Metab. Dispos. 30(5): 602-607, 2002.
  • National Toxicology Program: NTP toxicology and carcinogenesis studies of d-limonene (CAS No. 5989-27-5) in F344/N rats and B6C3F1 mice (gavage studies). Nat. Toxicol. Program Tech. Rep. Ser. 518: 1-165, 1990.
  • Pohanish, R.P. (editor): Dipentene. In, Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 1. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 970-972.

Date Last Revised: 01/04/2005

Monitoring Methods used by OSHA

Primary Laboratory Sampling/Analytical Method (SLC1):

  • sampling media: Charcoal Tube (100/50 mg sections)
    analytical solvent: Carbon Disulfide
    maximum volume: 10 Liters
    maximum flow rate: 0.2 L/min
    current analytical method: Gas Chromatography; GC/FID
    method reference: OSHA Analytical Method (OSHA PV2036)
    method classification: Partially Validated

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