LABORATORY CHEMICAL SAFETY SUMMARY: CHLOROFORM

Substance

Chloroform

 

 

(Trichloromethane)

 

 

CAS 67-66-3

 

Formula

CHCl3

 

Physical Properties

Colorless liquid

 

 

bp 61 °C, mp -63.5 °C

 

Slightly soluble in water (0.8 g/100 mL)

Odor

Ethereal, sweet odor detectable at 133 to 276 ppm (mean = 192 ppm)

Vapor Density

4.1 (air = 1.0)

 

Vapor Pressure

160 mmHg at 20 °C

 

Flash Point

Noncombustible

 

Toxicity Data

LD50 oral (rat)

908 mg/kg

 

LD50 skin (rabbit)

>20 g/kg

 

LC50 inhal (rat)

9937 ppm (47,702 mg/m3; 4 h)

 

PEL (OSHA)

50 ppm (240 mg/m3; ceiling)

 

TLV-TWA (ACGIH)

10 ppm (48 mg/m3)

Major Hazards

Low acute toxicity; skin and eye irritant.

Toxicity

The acute toxicity of chloroform is low by all routes of exposure. Inhalation can cause dizziness, headache, drowsiness, and nausea, and at higher concentrations, disorientation, delirium, and unconsciousness. Inhalation of high concentrations may also cause liver and kidney damage. Exposure to 25,000 ppm for 5 min can be fatal to humans. Ingestion of chloroform can cause severe burning of the mouth and throat, chest pain, and vomiting. Chloroform is irritating to the skin and eyes, and liquid splashed in the eyes can cause burning pain and reversible corneal injury. Olfactory fatigue occurs on exposure to chloroform vapor, and it is not regarded as a substance with adequate warning properties.

Chloroform 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 injury. There is some evidence from animal studies that chloroform is a developmental and reproductive toxin.

Flammability and Explosibility

Chloroform is noncombustible. Exposure to fire or high temperatures may lead to formation of phosgene, a highly toxic gas.



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