A pale yellow liquid with a pungent odor.
Intermediate for many insecticides, polyester resins, and flame retardants.
Registry Numbers and Inventories.
EC Index Number
Very toxic; Toxic; Harmful; Corrosive; Dangerous for the Environment
Agricultural Chemical and Pesticide; Tumorigen; Reproductive Effector; Primary Irritant
Swiss Giftliste 1
Japan ENCS (MITI)
Melting point, °C
Boiling point, °C
Vapor pressure, mmHg
0.052 (25 C)
Vapor density (air=1)
Odor Threshold Odor threshold 0.15 ppm
1.7105 g/cm3 (20 C)
Solubility in water
2 mg/L (Reacts)
37.5 g/s2 (20 C)
1.5644 (20 C)
Partition coefficient, pKow
Heat of vaporization
Hazards and Protection.
Tightly closed containers. Keep away from heat and water.
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.
Wear appropriate clothing to prevent any reasonable probability of skin contact. Wear eye protection to prevent any possibility of eye contact.
Wear positive pressure self-contained breathing apparatus (SCBA).
Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Attempt to stop leak if without undue personnel hazard. Use water spray to knock-down vapors. Land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. Cover solids with a plastic sheet to prevent dissolving in rain or fire fighting water. Absorb bulk liquid with fly ash or cement powder. Water spill: Use natural deep water pockets, excavated lagoons, or sand bag barriers to trap material at bottom. Remove trapped material with suction hoses. Use mechanical dredges or lifts to remove immobilized masses of pollutants and precipitates.
Incompatible with strong oxidizing and reducing agents Incompatible with many amines, nitrides, azo/diazo compounds, alkali metals (sodium), and epoxides.
Isolate hazard area and deny entry. Wear positive pressure breathing apparatus and special protective clothing. Fight fire from maximum distance. Dike fire control water for later disposal.Use dry chemical, carbon dioxide, water spray or foam for small fires. For large fires, use water spray, fog, or foam. Move hexachlorocyclopentadiene from fire area if this can be done without risk.
Toxic hydrogen chloride, chlorine, and phosgene gases may form in fires. In presence of moisture, will corrode iron and other materials; flammable and explosive hydrogen gas may collect in enclosed space. Will corrode iron and other metals in the presence of moisture. Reacts slowly with water to form hydrochloric acid; however, the reaction is not hazardous.
Toxic hydrogen chloride, chlorine, and phosgene gases may form in fires.
NIOSH REL: TWA 0.01 ppm (0.1 mg/m3)
Headache is common. Degenerative CNS changes have been seen in experimental animals.
Nausea may occur.
The major target organ for c56 toxicity is the lung, regardless of the exposure route. Cough, dyspnea, and chest discomfort have been reported in exposed humans. Experimental animals have developed pulmonary edema, pulmonary hemorrhages, and necrotizing bronchitis and bronchiolitis.
Skin irritation may occur from direct contact or vapor exposure. Direct skin contact with the liquid can cause dermal blistering and burns.
CONJUNCTIVITIS - Eye irritation is common. Irritation of the throat may be seen.
The possible benefit of early removal of some ingested material by cautious gastric lavage must be weighed against potential complications of bleeding or perforation. Activated charcoal activated charcoal binds most toxic agents and can decrease their systemic absorption if administered soon after ingestion. Activated charcoal: administer charcoal as a slurry (240 ml water/30 g charcoal). Usual dose: 25 to 100 g in adults/adolescents.
Move patient to fresh air. Monitor for respiratory distress. If cough or difficulty breathing develops, evaluate for respiratory tract irritation, bronchitis, or pneumonitis. Administer oxygen and assist ventilation as required. Treat bronchospasm with beta2 agonist and corticosteroid aerosols.
Remove contaminated clothing and wash exposed area thoroughly with soap and water. A physician should examine the area if irritation or pain persists. Treat dermal irritation or burns with standard topical therapy. Patients developing dermal hypersensitivity reactions may require treatment with systemic or topical corticosteroids or antihistamines.
Irrigate exposed eyes with copious amounts of tepid water for at least 15 minutes. If irritation, pain, swelling, lacrimation, or photophobia persist, the patient should be seen in a health care facility.
USCG CHRIS Code
Std. Transport #