NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005

Chlorine dioxide

CAS
10049-04-4

ClO2

RTECS
FO3000000
Synonyms & Trade Names

Chlorine oxide, Chlorine peroxide
DOT ID & Guide
9191 / 143 (hydrate, frozen)

Exposure
Limits

NIOSH REL: TWA 0.1 ppm (0.3 mg/m3) ST 0.3 ppm (0.9 mg/m3)
OSHA PEL: TWA 0.1 ppm (0.3 mg/m3)
IDLH
5 ppm See: 10049044
Conversion
1 ppm = 2.76 mg/m3
Physical Description
Yellow to red gas or a red-brown liquid (below 52°F) with an unpleasant odor similar to chlorine and nitric acid.
MW: 67.5
BP: 52°F
FRZ: -74°F
Sol(77°F): 0.3%
VP: >1 atm
IP: 10.36 eV
RGasD: 2.33
Sp.Gr: 1.6 (Liquid at 32°F)
Fl.P: NA (Gas) ? (Liquid)
UEL: ?
LEL: ?

Flammable Gas/Combustible Liquid
Incompatibilities & Reactivities

Organic materials, heat, phosphorus, potassium hydroxide, sulfur, mercury, carbon monoxide [Note: Unstable in light. A powerful oxidizer.]
Measurement Methods
OSHA ID126SGX, ID202
See: NMAM or OSHA Methods
Personal Protection & Sanitation
(See protection)
Skin: Prevent skin contact (liquid)
Eyes: Prevent eye contact (liquid)
Wash skin: When contaminated (liquid)
Remove: When wet (flammable)
Change: No recommendation
Provide: Eyewash (liquid), Quick drench (liquid)
First Aid
(See procedures)
Eye: Irrigate immediately (liquid)
Skin: Soap wash immediately (liquid)
Breathing: Respiratory support
Swallow: Medical attention immediately (liquid)
Respirator Recommendations
NIOSH/OSHA
Up to 1 ppm:
(APF = 10) Any chemical cartridge respirator with cartridge(s) providing protection against the compound of concern
(APF = 10) Any supplied-air respirator
Up to 2.5 ppm:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode
(APF = 25) Any powered, air-purifying respirator with cartridge(s) providing protection against the compound of concern
Up to 5 ppm:
(APF = 50) Any chemical cartridge respirator with a full facepiece and cartridge(s) providing protection against the compound of concern
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern
(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece
Emergency or planned entry into unknown concentrations or IDLH conditions:
(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
Escape:
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern/Any appropriate escape-type, self-contained breathing apparatus
Important additional information about respirator selection
Exposure Routes
inhalation, ingestion (liquid), skin and/or eye contact
Symptoms
Irritation eyes, nose, throat; cough, wheezing, bronchitis, pulmonary edema; chronic bronchitis
Target Organs
Eyes, respiratory system
See also: INTRODUCTION   See ICSC CARD: 0127   See MEDICAL TESTS: 0045