NIOSH Pocket Guide to Chemical Hazards


CAS 1746-01-6


RTECS HP3500000
Synonyms & Trade Names
Dioxin; Dioxine; TCDBD; TCDD; 2,3,7,8-TCDD [Note: Formed during past production of 2,4,5-trichlorophenol, 2,4,5-T & 2(2,4,5-trichlorophenoxy)propionic acid.]
DOT ID & Guide


NIOSH REL: Ca See Appendix A
OSHA PEL: none
IDLH Ca [N.D.] See: IDLH INDEX Conversion
Physical Description
Colorless to white, crystalline solid. [Note: Exposure may occur through contact at previously contaminated worksites.]
MW: 322.0
BP: Decomposes
MLT: 581°F
Sol: 0.00000002%
VP(77°F): 0.000002 mmHg
IP: ?

Sp.Gr: ?
Fl.P: ?
UEL: ?
LEL: ?

Incompatibilities & Reactivities
UV light (decomposes)
Measurement Methods
None available
See: NMAM or OSHA Methods
Personal Protection & Sanitation (See protection)
Skin: Prevent skin contact
Eyes: Prevent eye contact
Wash skin: When contaminated/Daily
Remove: When wet or contaminated
Change: Daily
Provide: Eyewash, Quick drench
First Aid (See procedures)
Eye: Irrigate immediately
Skin: Soap flush immediately
Breathing: Respiratory support
Swallow: Medical attention immediately
Important additional information about respirator selection
Respirator Recommendations NIOSH
At concentrations above the NIOSH REL, or where there is no REL, at any detectable concentration:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister having an N100, R100, or P100 filter. Click here for information on selection of N, R, or P filters./Any appropriate escape-type, self-contained breathing apparatus
Exposure Routes inhalation, skin absorption, ingestion, skin and/or eye contact
Symptoms Irritation eyes; allergic dermatitis, chloracne; porphyria; gastrointestinal disturbance; possible reproductive, teratogenic effects; in animals: liver, kidney damage; hemorrhage; [potential occupational carcinogen]
Target Organs Eyes, skin, liver, kidneys, reproductive system

Cancer Site [in animals: tumors at many sites]