Synonyms: Hexyl hydride; Normal-hexane

OSHA IMIS Code Number: 1380

Chemical Abstracts Service (CAS) Registry Number: 110-54-3

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: MN9275000

Department of Transportation Regulation Number (49 CFR 172.101) and 2012 Emergency Response Guidebook [4 MB PDF, 392 pages]: 1208 128

NIOSH Pocket Guide to Chemical Hazards - n-Hexane: Physical description, chemical properties, potentially hazardous incompatibilities, and more

U.S. Environmental Protection Agency (EPA) Hazard Summary - Hexane: Uses, sources and potential exposure, acute and chronic health hazard information, and more

National Toxicology Program (NTP) carcinogenic classification: Not listed

International Agency for Research on Cancer (IARC) carcinogenic classification: Not listed

EPA carcinogenic classification: Inadequate information to assess carcinogenic potential

EPA Inhalation Reference Concentration (RfC): 7x10-1 mg/m³

Agency for Toxic Substances and Disease Registry (ATSDR) Inhalation Minimal Risk Level (MRL): 0.6 ppm (chronic)

NIOSH Immediately Dangerous To Life or Health Concentration (IDLH): 1,100 ppm (10% LEL)

Notes on Other Potential Health Effects and Hazards

1. Vapor/air mixtures are explosive (NIOSH/IPCS 2000).
2. Impairment of color vision can occur that may not be noticeable (subclinical) without specific testing for it (Issever et al. 2002).
3. n-Hexane is metabolized via CYP2B6, CYP2E1, and alcohol dehydrogenase to 2,5-hexanedione, which, after acid treatment of urine, serves as a marker for biological monitoring of exposure (Bolt et al. 2003).
4. Suppression of immunoglobulin (IgG, IgM, and IgA) levels were noted from exposure to n-hexane (Karakaya et al. 1996). ATSDR discounted this study because reductions of immunoglobulins remained well within the normal ranges, so the toxicological significance cannot be assessed without further confirmatory studies (ATSDR 1999).
5. Commercial hexane contains a mixture of hexane isomers (n-hexane, 2-methyl pentane, 3-methyl pentane, 2,3-dimethylbutane), cyclohexane, methyl cyclopentane,pentane and heptane isomers The n-hexane content varies from 20 to 80%. (IPCS 1991)
6. The OSHA PEL applies to total hexane. The CalOSHA PEL applies to n-hexane.
7. The EPA IRIS RfC  and ATSDR  MRL apply to n-hexane.
8. The EPA RfC is based on decreased motor nerve conduction velocity observed ina sub-chronic inhalation study in rats. (Huang 1989).
9. Polyneuropathy has been observed in automotive technicians using aerosol brake cleaners containing 50%--60% hexane (composed of 20%--80% n-hexane), 20%--30% toluene, and 1%--10% each of methyl ethyl ketone (MEK), acetone, isopropanol, methanol, and mixed xylenes. (MMWR 2001).

Date Last Revised: 11/16/2012

Literature Basis:

• ACGIH: Documentation of the Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs) - Hexane (n-Hexane). 2001.
• ATSDR: Toxicological Profile for n-Hexane. July 1999.
• Bolt, H.M., Roos, P.H. and Thier, R.: The cytochrome P-450 isoenzyme CYP2E1 in the biological processing of industrial chemicals: consequences for occupational and environmental medicine. Int. Arch. Occup. Environ. Health 76(3): 174-185, 2003.
• California Occupational Safety & Health Standards Board: Initial [70 KB PDF, 11 pages] and Final [124 KB PDF, 10 pages] Statement of Reasons. July 6, 2006.
• EPA n-Hexane | IRIS n-hexane 2005
• Huang, J; Kato, K; Shibata, E; et al. (1989) Effects of chronic n-hexane exposure on nervous system-specific and muscle-specific proteins. Arch Toxicol 63:381-385.
• Issever, H., Malat, G., Sabuncu, H.H. and Yuksel, N.: Impairment of colour vision in patients with n-hexane exposure-dependent toxic polyneuropathy. Occup. Med. 52(4): 183-186, 2002.
• IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY, Health and Safety Guide No. 59, n-hexane, 1991.
• Karakaya A., Yücesoy B., Burgaz S., Sabir H.U., Karakaya A.E.: Some immunological parameters in workers occupationally exposed to n-hexane. Hum. Exp. Toxicol. 15(1): 56-8, 1996.
• MMWR n-Hexane--Related Peripheral Neuropathy Among Automotive Technicians --- California, 1999—2000, 2001
• NIOSH: Criteria for a Recommended Standard - Occupational Exposure to Alkanes (C5-C8). March 1977.
• NIOSH/IPCS: International Chemical Safety Cards - n-Hexane. April 13, 2000.

Laboratory Sampling/Analytical Method:

• sampling media: Charcoal Tube (100/50 mg sections, 20/40 mesh)
  analytical solvent: Carbon disulfide
  alternative solvent: (99:1) Carbon Disulfide:Dimethylformamide
  alternative solvent: (95:5) Methylene Chloride:Methanol
  maximum volume: 4 Liters
  maximum flow rate: 0.2 L/min
  current analytical method: Gas Chromatography; GC/FID
  method reference: NIOSH Analytical Method (NIOSH 1500)
  method classification: Partially Validated

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