# NIOSH Pocket Guide to Chemical Hazards
Nitrogen dioxide | CAS 10102-44-0
NO2 | RTECS QW9800000
Synonyms & Trade Names Dinitrogen tetroxide (N2O4), Nitrogen peroxide | DOT ID & Guide 1067 124
Exposure Limits | NIOSH REL: ST 1 ppm (1.8 mg/m3)
OSHA PEL†: C 5 ppm (9 mg/m3)
IDLH 20 ppm | Conversion 1 ppm = 1.88 mg/m3
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 | RGasD: 2.62 | Sp.Gr: 1.44 (Liquid at 68°F)
Fl.P: NA | UEL: NA | LEL: NA |
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.]
Measurement Methods NIOSH 6014; OSHA ID182
Personal Protection & Sanitation 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
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
See also: INTRODUCTION