Toxicity Profiles

RAGs A Format for Methylene Chloride - CAS Number 75092

Methylene chloride, also known as also known as dichloromethane, is a colorless organic liquid with a penetrating ether-like odor that does not occur naturally in the environment. Methylene chloride is used as a solvent in paint removers, degreasing agents, and aerosol propellants; as a polyurethane foam-blowing agent; as a process solvent in the pharmaceutical industry; and as an extraction solvent for spice oleoresins, hops, and caffeine.

Methylene chloride is readily absorbed from the lungs, the digestive tract, and to some extent through the skin. Breathing large amounts of methylene chloride may cause unsteadiness, dizziness, nausea, and a tingling or numbness of fingers and toes. Breathing smaller amounts of methylene chloride may decrease attention and accuracy in tasks requiring hand-eye coordination. Skin contact with methylene chloride causes burning and redness of the skin.

The primary adverse health effects associated with methylene chloride exposure are central nervous system (CNS) depression and mild liver effects. Neurological symptoms described in individuals occupationally exposed to methylene chloride included headaches, dizziness, nausea, memory loss, paresthesia, tingling hands and feet, and loss of consciousness. Major effects following acute inhalation exposure include fatigue, irritability, analgesia, narcosis, and death.

It is not known whether methylene chloride causes cancer in humans. Studies of workers exposed to methylene chloride have not recorded a significant increase in cancer cases above the number of cases expected for nonexposed workers; however, an increased cancer risk was seen in mice breathing large amounts of methylene chloride for a long time. Tumors were found in lungs and liver of exposed mice. Rats showed increases of benign mammary tumors. Based on inadequate evidence of carcinogenicity in humans and sufficient evidence in animals, U.S. EPA has placed methylene chloride in weight-of-evidence group B2, probable human carcinogen.

The following is a presentation of the toxicity information associated with Methylene Chloride.

Noncarcinogenic Health Effects
  • 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 100.
  • The Oral Chronic Reference Dose is based on the National Coffee Association study from 1982.
  • The Oral Chronic Reference Dose study target organ is liver.
  • The Oral Chronic Reference Dose study critical effect is toxicity.
  • The overall confidence in the Oral Chronic Reference Dose is medium.

  • The Inhalation Chronic Reference Concentration is 3.00E+00 (mg/m3).
  • The Inhalation Chronic Reference Concentration has a modifying factor of 1.
  • The Inhalation Chronic Reference Concentration has an uncertainty factor of 100.
  • The Inhalation Chronic Reference Concentration is based on the U.S. EPA study from 1989.
  • The Inhalation Chronic Reference Concentration study target organ is liver.
  • The Inhalation Chronic Reference Concentration study critical effect is toxicity.

  • The Dermal Chronic Reference Dose is 5.70E-02 (mg/kg-day).
  • The Dermal Chronic Reference Dose is based on a gastrointestinal absorption factor of 0.9500.

Carcinogenic Health Effects
  • The Oral Slope Factor is 7.50E-03 (mg/kg-day)-1.
  • The Oral Slope Factor study target organ is liver.
  • The Oral Slope Factor study cancer types are adenomas, carcinomas, nodules.
  • The Oral Slope Factor is based on the NTP study from 1986.

  • The Inhalation Unit Risk is 4.7E-04 (mg/m3)-1.
  • The Inhalation Unit Risk study target organs are liver and lung.
  • The Inhalation Unit Risk study cancer types are adenomas and carcinomas.
  • The Inhalation Unit Risk is based on the NTP study from 1986.

  • The Dermal Slope Factor is 7.89E-03 (mg/kg-day)-1.
  • The Dermal Slope Factor is based on a gastrointestinal absorption factor of 0.9500.