Todd DunningMAUnited States
Optical Materials for Laser SystemsPublished
Dec 24, 2025
Ammonia (NH₃)
Chemical Properties
Chemical Identity
CAS Number
7664-41-7
Formula
NH₃
Molecular Weight
17.03 g/mol
Exposure Limits Comparison
OSHA PEL
50 ppm
NIOSH REL
25 ppm
ACGIH TLV
25 ppm
Health Effects
Respiratory Irritation
Yes
Eye Irritation
Yes
Chemical Burns
Yes
Pulmonary Edema
Yes
Ammonia (NH₃) safety information
Comprehensive safety and handling requirements
Detection Monitoring
- Electrochemical
- Infrared
- Catalytic bead
- Colorimetric
- Dräger Ammonia 0.25/a
- Gastec 3L
- Kitagawa 105
| Sensor Types | ||||||||||
| Detection Range | 0-100 ppm typical | |||||||||
| Alarm Setpoints |
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| Colorimetric Tubes | ||||||||||
| Analytical Methods |
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| Odor Threshold | 5-50 ppm - provides good warning below toxic levels |
Environmental Impact
| Aquatic Toxicity | Toxic to fish at high concentrations. LC50 (fish, 96h): 0.5-2.0 mg/L un-ionized NH3. Unionized form highly toxic. | ||||
| Biodegradability | Readily biodegradable. Nitrifying bacteria convert to nitrate. | ||||
| Bioaccumulation | Does not bioaccumulate. Log Kow: -1.69. | ||||
| Soil Mobility | High mobility as gas. Volatilizes from soil. Absorbed as ammonium ion. | ||||
| Atmospheric Fate | Reacts with acids forming ammonium salts. Washed out by rain. Atmospheric residence: days. | ||||
| Ozone Depletion | false | ||||
| Reportable Releases |
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Ppe Requirements
| Respiratory | SCBA or supplied-air respirator for >25 ppm or unknown concentrations. Air-purifying with ammonia cartridge acceptable for ≤25 ppm. |
| Eye Protection | Chemical safety goggles, full face shield. Extremely irritating and corrosive to eyes. |
| Skin Protection | Neoprene, nitrile, or butyl rubber gloves. Chemical-resistant clothing. Liquid ammonia causes severe burns and frostbite. |
Reactivity
- Strong acids (violent exothermic)
- Halogens (explosive reactions)
- Heavy metal compounds
- Mercury
- Silver oxide
- Oxidizers
- Calcium hypochlorite
- Nitrogen
- Hydrogen
- Nitrogen oxides (in fire)
- Ammonia vapors
- Heat
- Acids
- Halogens
- Oxidizers
- Sparks
- Open flames
| Stability | Stable under normal conditions. |
| Polymerization | Will not polymerize |
| Incompatible Materials | |
| Hazardous Decomposition | |
| Conditions To Avoid | |
| Reactivity Hazard | Reacts violently with strong acids producing heat and ammonium salts. Explosive reaction with halogens. Attacks copper, brass, zinc, aluminum, and alloys. |
Regulatory Classification
- Acute toxicity (inhalation)
- Flammability
- Skin corrosion
- Serious eye damage
| Un Number | UN1005 (anhydrous), UN2672 (solution) | ||||||
| Dot Hazard Class | 2.2 (Non-flammable gas) or 2.3 (Toxic gas) depending on concentration | ||||||
| Dot Label | Non-flammable Gas or Poison Gas | ||||||
| Nfpa Codes |
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| Epa Hazard Categories | |||||||
| Sara Title Iii | true | ||||||
| Cercla Rq | 100 pounds (45.4 kg) |
Storage Requirements
- Acids (violent reaction)
- Halogens (chlorine, bromine)
- Heavy metals
- Oxidizers
- Mercury
- Silver compounds
- Calcium hypochlorite
| Temperature Range | Store cylinders <52°C. Keep away from heat. |
| Ventilation | Outdoor storage preferred. Indoor: mechanical ventilation with emergency backup. Ammonia gas detection mandatory. |
| Incompatibilities | |
| Container Material | Steel cylinders for compressed gas. Stainless steel for solutions. |
| Segregation | Separate from acids by 20 feet or firewall. Separate from oxidizers and halogens. Flammable gas storage. |
| Quantity Limits | Per fire code. Refrigeration systems subject to special regulations. |
| Special Requirements | Cylinder restraints mandatory. Leak detection system required. Post "FLAMMABLE GAS" and "CORROSIVE" signs. Emergency eyewash/shower within 25 feet. Avoid contact with copper, brass, zinc in piping. |
Produced From Contaminants
Produced From Materials
Exposure Limits
Regulatory exposure thresholds and safe concentration levels
- Osha Pel Ppm
- 50
- Osha Pel Mg M3
- 35
- Niosh Rel Ppm
- 25
- Niosh Rel Mg M3
- 18
- Acgih Tlv Ppm
- 25
- Acgih Tlv Mg M3
- 17
- Workplace Exposure
- Osha Peltwa_8hr: 50 ppm (35 mg/m³)stel_15min: nullceiling: nullNiosh Reltwa_8hr: 25 ppm (18 mg/m³)stel_15min: 35 ppm (27 mg/m³) - 15 minceiling: nullidlh: 300 ppmAcgih Tlvtwa_8hr: 25 ppmstel_15min: 35 ppmceiling: nullBiological Exposure Indices
Physical Properties
Physical characteristics and state information
- Boiling Point
- -33.34°C (-28°F)
- Melting Point
- -77.73°C (-107.9°F)
- Vapor Pressure
- 7510 mmHg @ 20°C
- Vapor Density
- 0.60 (Air=1)
- Specific Gravity
- 0.682 (liquid @ -33°C)
- Flash Point
- Not applicable (gas)
- Autoignition Temp
- 651°C (1204°F)
- Explosive Limits
- LEL: 15%, UEL: 28%
- Appearance
- Colorless gas, colorless liquid under pressure
- Odor
- Sharp, pungent, suffocating odor @ 5-50 ppm
Reactivity
Chemical reactivity and compatibility with other substances
- Stability
- Stable under normal conditions.
- Polymerization
- Will not polymerize
- Incompatible Materials
- Strong acids (violent exothermic)
- Halogens (explosive reactions)
- Heavy metal compounds
- Mercury
- Silver oxide
- Oxidizers
- Calcium hypochlorite
- Hazardous Decomposition
- Nitrogen
- Hydrogen
- Nitrogen oxides (in fire)
- Ammonia vapors
- Conditions To Avoid
- Heat
- Acids
- Halogens
- Oxidizers
- Sparks
- Open flames
- Reactivity Hazard
- Reacts violently with strong acids producing heat and ammonium salts. Explosive reaction with halogens. Attacks copper, brass, zinc, aluminum, and alloys.
Synonyms & Identifiers
Alternative names and chemical identifiers (CAS numbers)
- Synonyms
- Anhydrous ammonia
- NH3
- Ammonia gas
- Ammonia solution (aqueous)
- Common Trade Names
- Other Identifiers
- Rtecs NumberBO0875000Ec Number231-635-3Pubchem Cid222
