LABORATORY CHEMICAL SAFETY SUMMARY: CARBON TETRACHLORIDE

Substance

Carbon tetrachloride

(Tetrachloromethane)

CAS 56-23-5

 

Formula

CCl4

 

Physical Properties

Colorless liquid

bp 77 °C, mp -23 °C

Insoluble in water (0.05 g/100 mL)

 

Odor

Ethereal, sweet, pungent odor detectable at 140 to 584 ppm (mean = 252 ppm)

Vapor Density

5.3 (air = 1.0)

 

Vapor Pressure

91 mmHg at 20 °C

 

Flash Point

Noncombustible

 

Toxicity Data

LD50 oral (rat)

2350 mg/kg

 

LD50 skin (rabbit)

>20 g/kg

 

LC50 inhal (rat)

8000 ppm (4 h)

 

PEL (OSHA)

2 ppm (13 mg/m3)

 

TLV-TWA (ACGIH)

5 ppm (32.5 mg/m3)-skin

 

STEL (ACGIH)

10 ppm (65 mg/m3)

Major Hazards

Low to moderate acute toxicity; harmful to the liver, kidneys, and central nervous system.

Toxicity

The acute toxicity of carbon tetrachloride is low to moderate. Inhalation of carbon tetrachloride can produce symptoms such as dizziness, headache, fatigue, nausea, vomiting, stupor, and diarrhea. This substance is a depressant of the central nervous system, and inhalation of high concentrations causes damage to the liver, heart, and kidneys. Exposure to 1000 to 2000 ppm for 30 to 60 min can be fatal to humans. Ingestion of carbon tetrachloride leads to similar toxic effects, and swallowing as little as 4 mL can be lethal. Carbon tetrachloride irritates the skin, and prolonged contact may cause dryness and cracking. This substance is also slowly absorbed through the skin. Carbon tetrachloride liquid and vapor are also irritating to the eyes. The odor of carbon tetrachloride does not provide adequate warning of the presence of harmful concentrations.

Carbon tetrachloride shows carcinogenic effects in animal studies and is listed by IARC in Group 2B ("possible human carcinogen"). It is not classified as a "select carcinogen" according to the criteria of the OSHA Laboratory Standard. Prolonged or repeated exposure to this substance may result in liver and kidney damage. There is some evidence from animal studies that carbon tetrachloride may be a developmental and reproductive toxin in both males and females.



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