ABC of Safety in the Biological Sciences




Methylene chloride.
Colourless, volatile liquid with pleasant sweet odour.
Dichloromethane is incompatible with aluminium, magnesium and their alloys. Water absorption contributes to instability. Heating produces toxic fumes of hydrogen chloride and phosgene.
Forms a flammable vapour/air mixture at temperatures above ambient. Do not store close to heat or naked flame. It is toxic and has anaesthetic properties and is an eye and skin irritant. Acute exposure to the eyes causes pain and possible transient corneal injury. Prolonged skin contact causes irritation with localised reddening. Skin absorption does occur and will produce signs of toxicity. Inhalation and ingestion produce signs of narcosis and possible blood disorders.
Use a fume hood.
Toxic, avoid ingestion.
Avoid skin and eye contact.
Avoid inhalation of the vapour.
Keep away from heat or naked flames.
Keep away from moisture.
Use a fume hood which will keep levels of exposure below recommended threshold limits, i.e. below 200 ppm, or 350 mgm/m (NH & MRC, Australia). At levels of exposure above 200 ppm a respirator is recommended. If levels of exposure are expected to be excessively high use a self­contained breathing apparatus. Wear protective clothing. A long sleeved laboratory coat or gown, rubber gloves, safety goggles and a face mask as a minimum standard.
Skin ­ remove contaminated clothing, immediately wash the affected area with soap or mild detergent and large amounts of water until all evidence of the chemical has been removed (approximately 15 minutes). If irritation persists or narcosis develops seek immediate medical attention.
Eyes ­ immediately wash the affected eye with large amounts of water until all evidence of the chemical has been removed (approximately 15 minutes). If irritation persists seek medical attention.
Inhalation ­ remove from the area of exposure to fresh air. If breathing has stopped apply artificial respiration. Keep warm and allow to rest. Seek immediate medical attention.
Ingestion ­ rinse the mouth with water and give water to drink, do not induce vomiting. Seek immediate medical attention.
Store in a well ventilated, cool, dry atmosphere away from heat or incompatible chemicals.
Rubber gloves, laboratory coat and self contained breathing apparatus (or work in a fume hood).
Absorb on paper towels and allow to evaporate in the fume hood. Burn the paper. Wash the spill site with a soap solution.
The toxic liquid compounds concerned here are insoluble in water and cannot be burned. purify the contaminated liquid by distillation and place the purified distillate back on the shelf.
Disposal of according to any local regulations.


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