LABORATORY CHEMICAL SAFETY SUMMARY: TOLUENE DIISOCYANATE

Substance

Toluene diisocyanate

(TDI; 2,4-toluene diisocyanate; 2,4-diisocyanato-1-methyl benzene)

CAS 584-84-9

 

Formula

C9H6N2O2

 

Physical Properties

Colorless to pale yellow liquid

bp 251 °C, mp 21 °C

Insoluble in water (reacts exothermically)

 

Odor

Sharp, pungent odor detectable at 0.02 to 0.4 ppm

Vapor Density

6.0 (air = 1.0)

 

Vapor Pressure

0.05 mmHg at 25 °C

 

Flash Point

132 °C

 

Autoignition Temperature

>619 °C

 

Toxicity Data

LD50 oral (rat)

4130 mg/kg

 

LD50 skin (rabbit)

>10 g/kg

 

LC50 inhal (rat)

14 ppm/4 h (100 mg/m3; 4 h)

 

PEL (OSHA)

0.02 ppm(ceiling 0.14 mg/m3)

 

TLV-TWA (ACGIH)

0.005 ppm (0.036 mg/m3)

 

STEL (ACGIH)

0.02 ppm (0.14 mg/m3)

Major Hazards

Sensitizer by inhalation and skin contact; possible human carcinogen (OSHA "select carcinogen").

Toxicity

The acute toxicity of toluene diisocyanate by inhalation is high. Exposure to TDI can cause lung damage and decreased breathing capacity. Symptoms of exposure may include coughing, tightness of the chest, chest pain, nausea, vomiting, abdominal pain, headache, and insomnia. TDI irritates the skin, and eye contact can cause irritation with permanent damage if untreated. The oral acute toxicity of this substance is low. The odor of TDI does not provide an adequate warning to avoid overexposure.

Toluene diisocyanate has caused sensitization of the respiratory tract, manifested by acute asthmatic reaction upon return to work after a period of time away from exposure. Initial symptoms include coughing during the night, with difficult or labored breathing. Skin sensitization can also occur. Toluene diisocyanate is listed in IARC Group 2B ("possible human carcinogen"), is listed by NTP as "reasonably anticipated to be a carcinogen," and is classified as a "select carcinogen'' under the criteria of the OSHA Laboratory Standard.



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