Dichloromethane Quickview (CASRN 75-09-2)

Status of Data for Dichloromethane

File First On-Line: 01/31/1987; Last Significant Revision: 01/01/1991

Category (section)	Status	Last Revised
Oral RfD Assessment	On-line	03/01/1988
Inhalation RfC Assessment	No data	09/01/1991
Carcinogenicity Assessment	On-line	02/01/1995

Synonyms

75-09-2 Aerothene MM Chlorure de methylene DCM Dichlormethan, uvasol Dichloromethane

1,1-Dichloromethane. Freon 30 Methane dichloride Methane, dichloro- Methylene bichloride more...

Chronic Health Hazard Assessments for Noncarcinogenic Effects

Reference Dose for Chronic Oral Exposure (RfD)

Critical Effect	Point of Departure*	UF	MF	RfD
Liver toxicity	NOAEL : 5.85 mg/kg-day	100	1	6 x10-2 mg/kg-day

* The Point of Departure listed serves as a basis from which the Oral RfD was derived. See Discussion of Conversion Factors and Assumptions for more details.

• Principal and Supporting Studies (Oral RfD)
  • 2-year rat drinking water bioassay (NOAEL for males), National Coffee Association, 1982
• Confidence in the Oral RfD
  • Study -- High
  • Database -- Medium
  • RfD -- Medium

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Reference Concentration for Chronic Inhalation Exposure (RfC)

Not Assessed under the IRIS Program.

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Carcinogenicity Assessment for Lifetime Exposure

• Weight-of-Evidence Characterization
  • B2 (Probable human carcinogen - based on sufficient evidence of carcinogenicity in animals)
• Weight-of-Evidence Narrative:
  • Based on inadequate human data and sufficient evidence of carcinogenicity in animals; increased incidence of hepatocellular neoplasms and alveolar/bronchiolar neoplasms in male and female mice, and increased incidence of benign mammary tumors in both sexes of rats, salivary gland sarcomas in male rats and leukemia in female rats. This classification is supported by some positive genotoxicity data, although results in mammalian systems are generally negative.
  • This may be a synopsis of the full weight-of-evidence narrative. See IRIS Summary.

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Quantitative Estimate of Carcinogenic Risk from Oral Exposure

Oral Slope Factor(s)	Extrapolation Method
7.5 x10-3 per mg/kg-day	Linearized multistage procedure, extra risk

Drinking Water Unit Risks
2.1x10-7 per µg/L

Risk Level	Concentration
E-4 (1 in 10,000)	5x102 µg/L
E-5 (1 in 100,000)	5x101 µg/L
E-6 (1 in 1,000,000)	5 µg/L

• Dose-Response Data (Carcinogenicity, Oral Exposure)
  • Tumor Type: Hepatocellular adenomas or carcinomas (NTP) and hepatocellular cancer and neoplastic nodules (NCA)
  • Test Species: Mouse/ B6C3F1 (female, NTP; male, NCA)
  • Route: Inhalation, (NTP); oral, drinking water (NCA)
  • Reference: NTP, 1986; National Coffee Association (NCA), 1983

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Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure

Inhalation Unit Risk(s)	Extrapolation Method
4.7 x10-7 per µg/m3	Linearized multistage procedure, extra risk

Inhalation Concentrations at Specified Risk Levels

Risk Level	Concentration
E-4 (1 in 10,000)	2x102 µg/m3
E-5 (1 in 100,000)	2x101 µg/m3
E-6 (1 in 1,000,000)	2 µg/m3

• Dose-Response Data (Carcinogenicity, Inhalation Exposure)
  • Tumor Type: Combined adenomas and carcinomas
  • Test Species: Mouse/ B6C3F1, female
  • Route: Inhalation
  • Reference: NTP, 1986