NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005

Ammonia

CAS
7664-41-7

NH3

RTECS
BO0875000
Synonyms & Trade Names

Anhydrous ammonia, Aqua ammonia, Aqueous ammonia [Note: Often used in an aqueous solution.]
DOT ID & Guide
1005 / 125 (anhydrous)
2672 / 154 (10-35% solution)
2073 / 125 (>35-50% solution)
1005 / 125 (>50% solution)

Exposure
Limits

NIOSH REL: TWA 25 ppm (18 mg/m3) ST 35 ppm (27 mg/m3)
OSHA PEL: TWA 50 ppm (35 mg/m3)
IDLH
300 ppm See: 7664417
Conversion
1 ppm = 0.70 mg/m3
Physical Description
Colorless gas with a pungent, suffocating odor. [Note: Shipped as a liquefied compressed gas. Easily liquefied under pressure.]
MW: 17.0
BP: -28°F
FRZ: -108°F
Sol: 34%
VP: 8.5 atm
IP: 10.18 eV
RGasD: 0.60

Fl.P: NA (Gas)
UEL: 28%
LEL: 15%

[Note: Although NH3 does not meet the DOT definition of a Flammable Gas (for labeling purposes), it should be treated as one.]
Incompatibilities & Reactivities

Strong oxidizers, acids, halogens, salts of silver & zinc [Note: Corrosive to copper & galvanized surfaces.]
Measurement Methods
NIOSH 3800, 6015, 6016; OSHA ID188
See: NMAM or OSHA Methods
Personal Protection & Sanitation
(See protection)
Skin: Prevent skin contact
Eyes: Prevent eye contact
Wash skin: When contaminated (solution)
Remove: When wet or contaminated (solution)
Change: No recommendation
Provide: Eyewash (>10%), Quick drench (>10%)
First Aid
(See procedures)
Eye: Irrigate immediately (solution/liquid)
Skin: Water flush immediately (solution/liquid)
Breathing: Respiratory support
Swallow: Medical attention immediately (solution)
Respirator Recommendations
NIOSH
Up to 250 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 300 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*
(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 (solution), skin and/or eye contact (solution/liquid)
Symptoms
Irritation eyes, nose, throat; dyspnea (breathing difficulty), wheezing, chest pain; pulmonary edema; pink frothy sputum; skin burns, vesiculation; liquid: frostbite
Target Organs
Eyes, skin, respiratory system
See also: INTRODUCTION   See ICSC CARD: 0414   See MEDICAL TESTS: 0013