• 2,7-Dichlorodibenzodioxin
Colorless crystals.
Not used commercially in the usa.

Registry Numbers and Inventories.
RTECS class
Tumorigen; Reproductive Effector; Primary Irritant
Beilstein Reference

Formula mass
Melting point, °C
Boiling point, °C
1.647 g/cm3
Solubility in water
0.2 ppm
Partition coefficient, pKow
Heat of vaporization
69.51 kJ/mol

Hazards and Protection.
Keep in a cool, dry, dark location in a tightly sealed container or cylinder. Keep away from incompatible materials, ignition sources and untrained individuals. Secure and label area. Protect containers/cylinders from physical damage.
All chemicals should be considered hazardous. Avoid direct physical contact. Use appropriate, approved safety equipment. Untrained individuals should not handle this chemical or its container. Handling should occur in a chemical fume hood.
Chemical splash goggles in compliance with OSHA regulations are advised; however, OSHA regulations also permit other type safety glasses. Whre chemical resistant gloves. To prevent repeated or prolonged skin contact, wear impervious clothing and boots.
Wear a NIOSH-approved half face respirator equipped with an organic vapor/acid gas cartridge (specific for organic vapors, HCl, acid gas and SO2) with a dust/mist filter.
Small spills/leaks
If you spill this chemical, FIRST REMOVE ALL SOURCES OF IGNITION, then dampen the solid spill material with toluene, then transfer the dampened material to a suitable container. Use absorbent paper dampened with toluene to pick up any remaining material. Your contaminated clothing and absorbent paper should be sealed in a vapor-tight plastic bag for eventual disposal. Solvent-wash all contaminated surfaces with toluene followed by washing with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.
Extremely stable, even on heating to 700 C chlorodibenzo-para-dioxins.

Fire fighting
Fires involving this material can be controlled with a dry chemical, carbon dioxide or Halon extinguisher.

Exposure effects
Peripheral neuropathy, with sensory impairment and lower extremity weakness, central neuropathy, mental status changes, headache and dizziness occur after exposure. Mild exposure may result in asymptomatic EMG alterations. Dioxins have not been proven to produce adverse reproductive effects in humans. However, low birthweights, ectodermal dysplasia, and growth and neurological deficits have been associated with dioxin exposure. Data on spontaneous abortions, decreased sperm quality and feminizing alterations of sex hormones have been mixed. TCDD accumulates in breast milk, and neurolgical deficits and increases in T4 and TSH have been associated with lactational exposure. TCDD is considered an animal teratogen.
Right-upper-quadrant pain, anorexia, nausea and vomiting may be early symptoms. Pancreatitis occurred in one case of industrial exposure.
Dyspnea may be noted.
The initial dermal reaction is extensive inflammation of exposed areas with photosensitivity, followed by development of chloracne.

First aid
DO NOT INDUCE VOMITING. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. Be prepared to transport the victim to a hospital if advised by a physician.
IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used.
IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment.
First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.