The Risk Assessment Information System

RAGs A Format for 1,1,2,2-Tetrachloroethane - CAS Number 79345

1,1,2,2-Tetrachloroethane is a manufactured, colorless chemical that does not burn easily. It is volatile and has a sweet odor similar to chloroform. In the past, 1,1,2,2-Tetrachloroethane was used as a solvent, to clean and degrease metals, and in paints and pesticides. Commercial production of 1,1,2,2-tetrachloroethane for these uses has stopped in the United States. It presently is used only as a chemical intermediate in the production of other chemicals.

Two human studies suggested that between 50 and 97% of inspired 1,1,2,2-tetrachloroethane was retained in lungs. Breathing high levels of 1,1,2,2-tetrachloroethane in a closed room can cause fatigue, vomiting, dizziness, and possibly unconsciousness; however, most people recover from these effects once they are in fresh air. Breathing, drinking, or touching 1,1,2,2-tetrachloroethane can cause liver damage, stomachaches, lung damage, heart damage, dizziness, or death if you are exposed to large amounts for a long period of time. The health effects from long-term (365 days or longer) exposure to low levels of 1,1,2,2-tetrachloroethane are not known. It is also not known whether 1,1,2,2-tetrachloroethane will cause reproductive effects in humans.

It is not definitively known whether 1,1,2,2-tetrachloroethane causes cancer in humans. Army workers exposed to 1,1,2,2-tetrachloroethane vapor in a clothing processing plant had a very slight increase in death due to genital cancers, leukemia, or other lymphomas over workers not employed in a clothing plant. In a long-term study, 1,1,2,2-tetrachloroethane caused an increase in liver tumors in mice, but not in rats. Based on these results, 1,1,2,2-tetrachloroethane has been classified as Group C, possible human carcinogen.

The following is a presentation of the toxicity information associated with 1,1,2,2-Tetrachloroethane.

• The Oral Chronic Reference Dose is 6.00E-02 (mg/kg-day).
• The Oral Chronic Reference Dose has a modifying factor of 1.
• The Oral Chronic Reference Dose has an uncertainty factor of 300.
• The Oral Chronic Reference Dose is based on the Microbiological Associates study from 1994.
• The Oral Chronic Reference Dose study critical effects are hepatocellular vacuolization and increses in absolute and relative liver weights.
• The overall confidence in the Oral Chronic Reference Dose is low.
  
• The Dermal Chronic Reference Dose is 4.2E-02 (mg/kg-day).
  
• The Dermal Chronic Reference Dose is based on a gastrointestinal absorption factor of 0.7.

• The Oral Slope Factor is 2.00E-01 (mg/kg-day)^-1.
• The Oral Slope Factor study target organ is liver.
• The Oral Slope Factor study cancer type is carcinoma.
• The Oral Slope Factor is based on the NCI study from 1978.
  
• The Inhalation Unit Risk is 5.8E-02 (mg/m³)^-1.
• The Inhalation Unit Risk study target organ is liver.
• The Inhalation Unit Risk study cancer type is carcinoma.
• The Inhalation Unit Risk is based on the NCI study from 1978.
  
• The Dermal Slope Factor is 2.86E-01 (mg/kg-day)^-1.
• The Dermal Slope Factor is based on a gastrointestinal absorption factor of 0.7000.