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.



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