Skip directly to local search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

Enter search terms separated by spaces.

Nitrogen dioxide

Synonyms & Trade Names
Dinitrogen tetroxide (N2O4), Nitrogen peroxide
CAS No.
10102-44-0
RTECS No.
QW9800000
DOT ID & Guide
1067 124
Formula
NO2
Conversion
1 ppm = 1.88 mg/m3
IDLH
20 ppm
See: 10102440
Exposure Limits
NIOSH REL
: ST 1 ppm (1.8 mg/m3)
OSHA PEL
†: C 5 ppm (9 mg/m3)
Measurement Methods

NIOSH 6014;
OSHA ID182
See: NMAM or OSHA Methods
Physical Description
Yellowish-brown liquid or reddish-brown gas (above 70°F) with a pungent, acrid odor. [Note: In solid form (below 15°F) it is found structurally as N2O4.]
MW:
46.0
BP:
70°F
FRZ:
15°F
Sol:
Reacts
VP:
720 mmHg
IP:
9.75 eV
Sp.Gr:
1.44 (Liquid at 68°F)
Fl.P:
NA
UEL:
NA
LEL:
NA
RGasD:
2.62
Noncombustible Liquid/Gas, but will accelerate the burning of combustible materials.
Incompatibilities & Reactivities
Combustible material, water, chlorinated hydrocarbons, carbon disulfide, ammonia [Note: Reacts with water to form nitric acid.]
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
irritation eyes, nose, throat; cough, mucoid frothy sputum, decreased pulmonary function, chronic bronchitis, dyspnea (breathing difficulty); chest pain; pulmonary edema, cyanosis, tachypnea, tachycardia
Target Organs
Eyes, respiratory system, cardiovascular system
Personal Protection/Sanitation
(See protection codes)
Skin: Prevent skin contact
Eyes: Prevent eye contact
Wash skin: When contaminated
Remove: When wet or contaminated
Change: No recommendation
Provide: Eyewash, Quick drench
First Aid
(See procedures)
Eye: Irrigate immediately
Skin: Water flush immediately
Breathing: Respiratory support
Swallow: Medical attention immediately
Respirator Recommendations

NIOSH

Up to 20 ppm:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode£
(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

See also: INTRODUCTION   See ICSC CARD: 0930   See MEDICAL TESTS: 0164
 

Order NIOSH Publications

Contact Us:
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Rd. Atlanta, GA 30333, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO