LABORATORY CHEMICAL SAFETY SUMMARY: AMMONIA (ANHYDROUS)

Substance

Ammonia (anhydrous)

CAS 7664-41-7

 

Formula

NH3

 

Physical Properties

Colorless gas

bp -33 °C, mp -78 °C

Highly soluble in water (89.9g/100 mL at 0 °C)

 

Odor

Intense pungent odor detectable at 17 ppm

 

Vapor Density

0.59 (air = 1.0)

 

Vapor Pressure

8.71 atm at 21 °C

 

Autoignition Temperature

690 °C

 

Toxicity Data

LD50 oral (rat)

350 mg/kg

 

LC50 inhal (rat)

2000 ppm (4 h)

 

PEL (OSHA)

35 ppm (27 mg/m3)

 

TLV-TWA (ACGIH)

25 ppm (17 mg/m3)

 

STEL (ACGIH)

35 ppm (27 mg/m3)

Major Hazards

Extremely irritating and corrosive to the eyes, skin, and respiratory tract.

Toxicity

Ammonia gas is extremely corrosive and irritating to the skin, eyes, nose, and respiratory tract. Exposure by inhalation causes irritation of the nose, throat, and mucous membranes. Lacrimation and irritation begin at 130 to 200 ppm, and exposure at 3000 ppm is intolerable. Exposure to high concentrations (above approximately 2500 ppm) is life threatening, causing severe damage to the respiratory tract, resulting in bronchitis, chemical pneumonitis, and pulmonary edema, which can be fatal. Eye contact with ammonia vapor is severely irritating, and exposure of the eyes to liquid ammonia or mists can result in serious damage, which may result in permanent eye injury and blindness. Skin contact with ammonia vapor, mists, and liquid can cause severe irritation and burns; contact with the liquid results in cryogenic burns as well. Ingestion of liquid ammonia burns the tissues, causing severe abdominal pain, nausea, vomiting, and collapse and can be fatal. Ammonia gas is regarded as having adequate warning properties.

Ammonia has not been found to be carcinogenic or to show reproductive or developmental toxicity in humans. Chronic exposure to ammonia can cause respiratory irritation and damage.



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