. "Appendix B: Laboratory Chemical Safety Summaries." Prudent Practices in the Laboratory: Handling and Disposal of Chemicals. Washington, DC: The National Academies Press, 1995.
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Prudent Practices in the Laboratory: Handling and Disposal of Chemicals
LABORATORY CHEMICAL SAFETY SUMMARY: DICHLOROMETHANE
Substance
Dichloromethane
(Methylene chloride; aerothene MM)
CAS 75-09-2
Formula
CH2Cl2
Physical Properties
Colorless liquid
bp 40 °C, mp -97 °C
Slightly soluble in water (1.32 g/100 mL)
Odor
Odor threshold 160 to 230 ppm
Vapor Density
2.93 (air = 1.0)
Vapor Pressure
440 mmHg at 25 °C
Flash Point
Noncombustible
Autoignition Temperature
556 °C
Toxicity Data
LD50 oral (rat)
1600 mg/kg
LC50 inhal (rat)
88,000 mg/m3; 30 min
PEL (OSHA)
500 ppm (8 h)
TLV-TWA (ACGIH)
50 ppm
Major Hazards
Low acute toxicity; skin and eye irritant.
Toxicity
Dichloromethane is classified as only slightly toxic by the oral and inhalation routes. Exposure to high concentrations of dichloromethane vapor (>500 ppm for 8 h) can lead to lightheadedness, fatigue, weakness, and nausea. Contact of the compound with the eyes causes painful irritation and can lead to conjunctivitis and corneal injury if not promptly removed by washing. Dichloromethane is a mild skin irritant, and upon prolonged contact (e.g., under the cover of clothing or shoes) can cause burns after 30 to 60 min exposure.
Dichloromethane is not teratogenic at levels up to 4500 ppm or embryotoxic in rats and mice at levels up to 1250 ppm.
Flammability and Explosibility
Noncombustible. Dichloromethane vapor concentrated in a confined or poorly ventilated area can be ignited with a high-energy spark, flame, or high-intensity heat source.
Reactivity and Incompatibility
Reacts violently with alkali metals, aluminum, magnesium powder, potassium t-butoxide, nitrogen tetroxide, and strong oxidizing agents.
