chemical information


Chemical Class:

Organochlorine Pesticide (OC)

Manufacturing/Use Status

use/production has been voluntarily discontinued in the U.S.

Found in these people:

Michael Lerner, Baby #6, Baby #3, Baby #10, Baby #7, Baby #5, Baby #9, Baby #2, Baby #4, Baby #1, Baby #8, Kathy Fowler, Anonymous Adult 1, U.S. Representative Louise Slaughter, Sara Corbett

Found in these locations:

Bolinas, CA; Rockville, MD; Upstate New York, NY; NY, USA


Exposure to high levels of hexachlorobenzene (HCB) can cause death in humans. In Turkey during the mid- to late-1950s, a fungicide containing 10 percent HCB was used to make bread, resulting in an extremely high rate of infant mortality (95 percent) in breast-fed babies born to mothers who ate the bread. The infants who died had skin lesions, cardio-respiratory failure, weakness and convulsions.

Hexachlorobenzene is "reasonably anticipated" to be a human carcinogen on the basis of laboratory animals studies (liver and thyroid tumors), and has been associated with thyroid cancer, soft tissue sarcoma and brain cancer in men living near a factory in Flix, Spain that produced large amounts of HCB (and other organochlorines) for decades (NTP 2002). Non-cancer effects include: altered liver enzymes levels and kidney function; arthritis; skin lesions and photosensitivity; osteoporosis (which led to shortening of fingers due to osteoporosis of the hand bones); hirsutism; enlarged thyroid; porphyria; possible decreased thyroid hormone (thyroxin or T4) and decreased immune system status.

Reproductive and developmental effects include decreased growth, spontaneous abortion and possible impairment of the development of locomotor skills in newborn babies and decreased growth. HCB also causes neurotoxicity in adulthood following development exposure. Symptoms include weakness, spontaneous tingling or burning sensations, polyneuropathy, delayed muscle contraction after contraction, jerkiness of movement like that seen in Parkinson's disease. Other effects observed in adults exposed as children include osteoporosis of hand bones, small hands, swelling and spindling of fingers (ATSDR 2002b). While HCB exposure has not been definitively linked to impaired immune function in humans, exposure to several organochlorines (including HCB) has been associated increased risk of otitis media (inflammation of the middle ear) in the first year of life (Dewailly 2000). A German study found that HCB levels (and heptachloroepoxide) were higher in a group of boys undergoing surgery for undescended testicles compared to boys with no testicular abnormalities (Hosie 2000).

In laboratory animals, HCB causes liver and thyroid tumors (NTP 2002). Non-cancer effects include lung toxicity (cellular effects and increased lipid content); skin lesions; liver toxicity (tumors, increased weight, altered enzyme levels, cellular effects); kidney/renal toxicity (increased kidney weight, cellular changes); hematological effects (anemia, decreased red blood cell count and hemoglobin); porphyria, which is a cluster of disorders of heme biosynthesis (heme is an oxygen-binding pigment produced by most cells); immunotoxicity (impairment of pulmonary immune defense, increased number of white blood cells, increased immunoglobulin E (often increased in people who have allergies), increased spleen weight, cellular effects on the spleen, thymus atrophy, immunosuppression, increased susceptibility to tumor challenge, increased lymphocyte count, increased lymph node weight); neurotoxicity (altered phospholipid content in brain, tremors, muscle weakness, convulsions, irritability, lethargy, loss of muscle coordination, paralysis, muscle twitches, hyperexcitability, decreased nerve conduction velocity); gastrointestinal tract lesions and adrenal toxicity (tumors, increased weight, cellular effects). HCB also causes many effects on endocrine organs such as hypothyroidism (decreased T4, decreased T3, increased TSH); increased thyroid weight; increased thyroid iodide uptake; thyroid alveolar adenoma; increased vitamin D3 and parathyroid hormone; excess urinary glucose; decrease adrenal hormone (corticosterone); altered progesterone; decreased ovulatory levels of estradiol.

Reproductive and developmental effects include ovarian toxicity (cellular changes, oocyte lesions); increased length of menstrual cycle; blocked ovulation; decreased fertility; delayed testicular development; decreased litter size; decreased neonatal body weight; neonatal death; hyperactivity in young rats; skeletal malformations and decreased immune function in animals exposed during development (ATSDR 2002b).


Organochlorine chemical, a class largely banned in the U.S. that builds up in the body over time, linked to cancer and reproductive harm.

Hexachlorobenzene has been found in 19 of the 27 people tested in EWG/Commonweal studies. It has also been found in 155 of the 4,821 people tested in CDC biomonitoring studies.

Top health concerns for Hexachlorobenzene (References)

health concern or target organ weight of evidence
Reproduction and fertilityunknown

Results for Hexachlorobenzene

in blood serum (lipid weight)

Showing results from EWG/Commonweal Study #1, industrial chemicals and pesticides in adults, EWG/Commonweal Study #4, industrial chemicals and pesticides in cord blood, EWG Study #8, chemicals in mother and 2 children, San Francisco Reporter, EWG Study #3, industrial chemicals and pesticides in adults

EWG/Commonweal results

  • geometric mean: 1.05 ng/g (lipid weight) in blood serum
  • found in 19 of 27 people in the group

CDC biomonitoring results

  • geometric mean: 11.7 ng/g (lipid weight) in blood serum
  • found in 155 of 4821 people in the group
ng/g (lipid weight) in blood serum 381

Hexachlorobenzene results

Detailed toxicity classifications (References)

classification governing entity/references
Reproductive effects - weight of evidence unknown/unassessedDamgaard, I. N., N. E. Skakkebaek, et al. (2006). Persistent pesticides in human breast milk and cryptorchidism. Environ Health Perspect 114(7): 1133-8.