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Hexachlorobenzene Chemical Sampling Information
Hexachlorobenzene

General Description
    Synonyms: HCB; Perchlorobenzene; Pentachlorophenylchloride; Phenyl perchloryl

    OSHA IMIS Code Number: 1376

    Chemical Abstracts Service (CAS) Registry Number: 118-74-1

    NIOSH, Registry of Toxic Effects (RTECS) Identification Number: DA2975000

    Department of Transportation Regulation Number (49 CFR 172.101) and Guide: 2729 152

    Chemical Description and Physical Properties: Colorless to white solid in various forms.
      molecular formula: C6Cl6
      molecular weight: 284.76
      boiling point: 323-326°C
      vapor pressure: 0.001 Pa @ 20°C
      melting point: 231°C
Exposure Limits
    American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): 0.002 mg/m3 TWA; Skin; Appendix A3 - Confirmed Animal Carcinogen with Unknown Relevance to Humans
Health Factors
    National Toxicology Program (NTP) carcinogenic classification: Reasonably Anticipated to be a Human Carcinogen

    International Agency for Research on Cancer (IARC) carcinogenic classification: Group 2B, Possibly carcinogenic to humans

    Environmental Protection Agency (EPA) carcinogenic classification: Group B2, Probable Human Carcinogen

    Potential symptoms: INGES. ACUTE: Headache, nausea, vomiting; loss of sensory perception, numbness of hands and arms, partial paralysis of arms and legs, loss of muscle control; apprehension, excitement, tremors, convulsions, coma; INGES. CHRONIC (delayed symptoms): Porphyrinuria (red or dark urine); enlarged liver; goiter (enlarged thyroid); loss of appetite; photosensitivity, bullae (large blisters), severe mutilating scars, hyperpigmentation (darkening of skin), hirsutism (excessive hair); relatively painless arthritic changes, osteoporosis in hand bones, small hands; weakness, paresthesia, myotonia (temporary failure of muscle relaxation), cogwheeling (jerkiness of muscle contraction). In nursing infants: weakness, pink sores, convulsions, death.

    Health Effects: Nervous System Disturbances (HE7); Chronic Toxicity---Liver, Thyroid, Skin, Developmental Toxicity, Death of Nursing Infants (HE3).

    Affected organs: CNS, liver, reproductive system (ovaries), thyroid, skin, bone

    Notes:
    1. OSHA does not have a PEL for hexachlorobenzene.
    2. Hexachlorobenzene is an OSHA Select Carcinogen.
    3. Infants and children may be more susceptible than adults to the neurotoxicity of hexachlorobenzene, and symptoms of toxicity may persist for more than 30 years.
    4. CYP3A4 is one of the cytochrome P450s that biotransform hexachlorobenzene to pentachlorophenol, which can be further metabolized to the reactive metabolite, tetrachlorohydroquinone. Most hexachlorobenzene, however, is slowly excreted unchanged in the feces over a period of years.
    5. EPA's oral reference dose (daily oral exposure likely to be without an appreciable risk of deleterious effects during a lifetime) for hexachlorobenzene is 0.0008 mg/kg/day.
    6. Hexachlorobenzene should not be confused with benzene hexachloride (hexachlorocyclohexane), the gamma isomer of which is known as the pesticide lindane.

    Date Last Revised: 09/08/2005

    Literature Basis:
      Agency for Toxic Substances and Disease Registry (ATSDR): Toxicological profile for hexachlorobenzene. Atlanta: ATSDR, 2002, 357 pp.
    • EPA Air Toxics Website: Hexachlorobenzene. U.S. Environmental Protection Agency Technology Transfer Network.
    • Pohanish, R.P. (editor): Hexachlorobenzene. In, Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 1. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 1234-1236.
Monitoring Methods used by OSHA
    Laboratory Sampling/Analytical Method:

    • sampling media: Glass Fiber Filter (37 mm)
      analytical solvent: Toluene
      maximum volume: 480 Liters   maximum flow rate: 2.0 L/min
      current analytical method: Gas Chromatography; GC/ECD
      method reference: OSHA SLTC In-House File
      method classification: Not Validated
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Page last updated: 09/05/2006

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